Tunnelling workmen really could meet up with a German submarine on its last dive under Dartmouth's Coronation Park – but probably not on their current heading.

Dartmouth Museum bosses say the town's submarine legend is true – and they have the photographs to prove it.

And there could even be a motor torpedo boat down there as well.

But whether the US forces buried tonnes of equipment under the park after the Second World War because they couldn't be bothered to take it home with them is another matter.

But who knows what currently unread museum documents could turn up, said museum trustees chairman David Lingard.

South West Water is currently trying to tunnel under the tennis courts on Coronation Park to lay a new sewer to replace the one that constantly backs up and floods homes in Coombe Road.

The alternative to tunnelling would have been the massively expensive job of digging up all the tennis courts which underwent a £90,000 facelift less than a year ago.

The issue of the First World War German submarine was raised after the water company took months to decide what to do about the sewer amid concerns about what lies under the park – which was part of the Dart estuary until the 1930s.

Mr Lingard has now revealed the U-boat story is not a legend and it really does lie beneath the park – although it is not likely to be anywhere near where the water workers plan to bore.

He said that from the photographs it is likely that the submarine is underground somewhere in the area near the Higher Ferry slipway, which the district council rents out for boat storage.

He also dug up old newspaper cutting suggesting a torpedo boat is also under the park, which was known as Coombe Mud before the estuary was filled in and the embankment built between 1928 and 1929 by unemployed miners from Wales.

As far as the submarine is concerned, Mr Lingard said: 'It's not legend at all. We have photographs. It's one of those things that turn up as legend because it is a nice story, but in this case it turns out to be true.'

However, he did point out that there was still some doubt as to whether the old sub was German or British.

Another possible myth about the park is that the US forces, who used Dartmouth as a set-off point for D-Day in 1944, still had tonnes of military equipment stored in the town when peace was declared in 1945.

Because it was not cost-effective to ship it back across the Atlantic, the story is they buried it under the park instead.

Mr Lingard said: 'We don't have any proof of that, so I think it may well be in the realm of legends.'

But he pointed out that the museum has two filing cabinet drawers full of documents that volunteers were slowly but surely going through and cataloguing.

'Only the other day we discovered papers about a Second World War radar station in Kingswear. Things like that keep turning up,' he said.