Experts had long thought the mighty stone foundations of the Clifton Suspension Bridge were as solid as the bedrock they stood upon. The experts were wrong.

In fact, they are filled with vast vaults, and until just recently, no one knew they were here. Quite how that was possible is a tale now being told by the bridge which is now occasionally opening up the hidden spaces to the public.


A large suspension bridge spanning the deep Avon gorge seems like a sensible idea, to save people going down to the river and back up again, but there never was a road here, there was never a need to go down a steep path and up the other side. The road is as new as the bridge.

Travelers could easily use the bridge a bit further down river in Bristol itself, but it was old and narrow, so when Bristolian merchant William Vick left a bequest in his will of £1,000 in 1753 for a road and bridge, it seemed likely that something would be built soon.

However, it took another hundred years for anything to happen, and by then the Admiralty had a rule that no bridge could be built unless it offered 100 feet of clearance for shipping.

That ruled out a bridge in Bristol, but permitted one at the top of the nearby Avon gorge. After many designs, delays, a riot, some bankruptcies and numerous other woes, a new road and mighty suspension bridge over the Avon finally opened in 1864 — 111 years after it was planned.


Apart from the very obvious suspension bridge itself, almost as impressive are the massive stone foundations which perch on the steep sides of the gorge and support the two tall towers. It was these which were to hold the secret of the lost vaults.

It seems that while the original and detailed plans of the suspension part of the bridge exist, the plans for the foundations were lost at some point. Possibly due to there being two different companies building them, or the various financial difficulties they got into. Whatever the reason, the plans were lost.

Over the years, people speculated about whether the foundations were hollow, and at times, deep drills were sent probing in, but always ran deep through stone.

It was obvious that the foundations were solid.

But, in 2002, while the paving slabs were being lifted for replacement works, a manhole cover was found on the Bristol side, and it showed a small brick vault containing an old coal stove, probably used by the original builders.

After a diversion to find a fake skeleton to put inside and only then notify the Bridge Master, all eyes turned to the other side of the Avon gorge, where the much larger foundations stood. Was there a manhole cover over there as well?

And yes, a manhole cover was found, but in this case it went down a deep shaft, which upon inspection led off to other shafts, and then, to massive vaults. Twelve in total.

Vast and for 140 years, they had vanished from view, and from memory.

If you’re both a communication between the two sides of the gorge, but also a major tourist attraction, you’re going to want to show off your newly discovered heritage, so for the past decade, works have been under way to open up these hidden spaces.

A sliver of land belonging to the National Trust next to the bridge offers a steep path down to a vertical ladder with perilous views over the gorge, to a narrow landing where engineers have drilled out a new entrance in the side of the bride.

It’s here that you might also appreciate why previous probes might have missed the vaults, as the walls at this thinnest point are still nearly 2 metres thick. A vast plug of stone was removed to create this new entrance, and they’ve kept the massive block in storage, just in case they want to seal the space up once more.


Hard hats firmly secured, passing through this newest addition to the bridge, and into the first of the huge vaults. Do try not to stop and stare in amazement at the space which seems bigger than the bridge should be able to contain.

The arched roof is now decorated by fine calcite straws — or stalactites — that add a Christmas tree effect to the space.

Using the International Standard for Measuring Things, the vaults are about the height of three double-decker buses.

A hole in the roof is now known to lead to another previously lost manhole cover, right in the middle of the road above, and if you stand silent, the rumble of motorists can be heard through the stone.


During construction, the builders didn’t smooth off the original bedrock but built around it, so here in a carefully constructed manmade stone vault, is a massive red outcrop of raw cliff face.

Crouching down to go inside and another smaller, and original tunnel leads into a second vaulted space, which has now been fitted with wooden flooring and metal steps up to the still mysterious round shafts.


It’s an immense space, and although once you have seen all there is to see there’s not much to see, it’s the experience of standing in this long lost space that is enthralling.

Soak up the atmosphere of the chill damp air and admire Isambard Kingdom Brunel’s ingenuity.


And yet you have seen but a small fraction of what’s down here. The vaults are on two levels, and visits are to the upper set, but in the far end is the recently installed metal staircase down to the lower level, which is still off limits.

Twelve vaults in total, you have seen two.

After a while, it’s time to pass back out into green and wooded lands, to climb up that metal staircase, to surrender hard hats and return to a normality which is now enlivened by what you’ve seen.


Walking back across the bridge, noticing how the western tower had corners cut at angles, while the eastern side were nicely squared. One of the great mysteries of the bridge was why — but the discovery of the vaults answered that long unanswered question.

But to find out what the answer is, you will need to go on a tour, and they are planned to resume from next March. Keep a very close eye on this page for details.



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  1. E says:

    Another great post!

    Here’s to 10 more years of the same!

    • Ed says:

      You mean 16 years, I don’t know where you get 10, 10 is a silly number, maybe you’ve been hitting the scotch too hard, what?

    • Ray Brown says:

      the Clifton vault was found by chance in August 1999, the first entrance to the Leigh woods vaults were found because they were looked for in November 1999,but never explored, in 2002 the second vault entrance was found not by chance but because its position was calculated, and if you look at the picture of the guy sat with his legs dangling down the hole you can see how deep the top of the entrance was, notice that there was no other paving disturbed, how do I know this — its because I am the guy that found them all.

  2. skankhunt42 says:

    Your writing reads like a late night infomercial, absolutely terrible. End yourself.

    • andyp1972 says:

      Ian Visits is a free (presumably voluntary) blog. If you don’t like it then don’t read it!

  3. Ian says:

    Great post.

  4. bill says:

    Fine article but Can you make clear which is the eastern and which the western side? Had to go for a map to see which is the bristol side (re the diferences in the tower bases) thanks…

  5. Ray Brown says:

    the blog is good,but the information you have written about the tour is what the Tour person tells you from a script. but in truth the Clifton Vault was found by chance in August 1999 (not 2002) after a small hole appeared in the formation, investigating the hole with an iron bar and not feeling any bottom, the hole was excavated and made bigger which revealed a arched doorway into the Vault, where you can see the stepped foundation of the Tower inside the Vault, the fire or oven is outside the doorway and built into the abutment wall.
    If you look at the Clifton Tower it has a vertical join where it has been squared off but would have looked the same as the Leigh Woods Tower with a chamfered edge but Smaller, after recalculating it was Squared off to strengthen it to bear the weight of the bridge deck and the chains, The first vault entrance on the Leigh Woods was discovered at the end of November 1999 because it was excavated for on the Bristol side of the tower and not because it was found by chance, close to the abutment wall there is evidence of there being a building being there and is under the paving of the viewing area that you stand on to look across the gorge to the Clifton tower, the entrance to the shaft was found halfway along the abutment in line with the centre of the Tower and it had 2 pieces of timber that looked like railway sleepers.
    In 2002 we were called back to excavate on the opposite side of the Leigh Woods Tower, after the Bridge master John Mitchel had a survey done by geo physics believing there to be more Voids or Hollows under the paving and had it all marked out. I did not agree with the findings and with Mr Mitchel’s permission I made my Calculations and excavated straight on top of the shaft with the same kind of timber covering, Mr Mitchel was so Amazed that he took the photo of me with my legs dangling over the hole, if you look at the photo you can see how deep the shaft was and that no other paving was disturbed, so no way was it found by chance and if the first shaft would have been explored in 1999 the vaults would have been found then. The Leigh Woods Tower is a Meter lower than the Clifton Tower, and with its chamfered edges it eases the wind oscillation around the Tower, The Clifton Tower has what looks like windows for the wind to blow through and around the Tower. With what is told I still believe that the Clifton Tower was Brunel’s datum starting point for his measurements to work within the span that Thomas Telford had specified for a Suspension Bridge, For Brunel to achieve this he had to come down the Leigh Woods Cliff face and build the Tower with a series of 12 Vaults to Anchor it, I have spent 14 years in research about the Leigh woods Abutment and there was a massive amount of money spent drilling and fixing steel and the masonry to the cliff face.
    There is a great deal more that I can write about but the Vaults are the foundations, Each Tower was Built with the chains Anchored deep into the road and is 74 meters from the centre of the Tower, With the Leigh Woods Tower Being a Meter Lower it Transfers the loading through and across the Vaults to the Anchor Points. So put the whispers and the Skeleton to bed the only vault found by chance was the Clifton side,
    Ray Brown.

  6. Hello There, I would like to know if it is possble to take some photographs of the Vaults and it would be nice to have photographs of the Vaults, I have been living here in Bristol for 15 years and i never Knew they were there, I mean the Vaults. I would like to see them soon.

  7. Rob Charlton says:

    Who do we contact to go on a tour is there a number or an email address

  8. edward jennings says:

    Hi As a child I visited the bridge many times, I am 73 years old it was when I down loaded a picture as wallpaper of the bridge.
    The picture shows writing on the right Colum looking to Bristol and I can’t find any info on it, so can you please tell me what is written on said Colum.
    I thank you for any info all the best Ted

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