DELIGHTED dace, perky perch and bouncing barbel will soon be able to swim upstream into Oxford for the first time in 400 years.

That is thanks to the team behind a £3.2m hydroelectric power plant at Sandford on Thames who have installed a new artificial stream around their facility.

Because there has been a weir on the site since at least 1630, this will be the first time in four centuries that dace, roach and perch will be able to get further upstream.

If other weirs downstream were to replicate the fish pass, it could even one day allow migrating salmon to leap upstream all the way into the centre of Oxford as they did centuries ago.

Sandford Hydro project director Adriano Figueiredos explained: "It basically looks like a kind of wiggly stream going around the hydro which they can swim up.

"There are concrete sections at the top and bottom then in the middle we've created a natural stream which we're going to fill with reeds to create habitat areas."

The team are even creating little pools along the way where the fish can stop along their way and rest.

The pass was designed for the Sandford Hydro team by Environment Agency expert Darryl Clifton-Dey.

He said: "What you find in the Thames is that because you've got so many weird put in for navigation reasons hundreds of years ago, they hold back the water and create a barrier which prevents fish populations swimming upstream: that means populations become fragmented and their habitat gets degraded.

"This fish pass is effectively like a new piece of river going around the weir: species like bullhead, stickleback and stone loach that are generally more slow moving and couldn't swim up the weir, they can now get upstream."

In fact, this particular type of fish pass, which is useable by all species of fish, is practically unique in the UK.

Mr Clifton-Dey said a similar one recently dug at Rushey near Faringdon was later found to have 600 fish living and breeding in it.

So, as Mr Figueiredos explained: "If one day all the locks had fish passes like ours we could get salmon up in Oxford just like we used to centuries ago."

He added: "We're not just generating renewable energy, we're also helping the biodiversity for years to come."

What's more, the fabulous fish pass has been created thanks to a generous £100,000 loan from taxpayers.

Oxford City Council agreed to lend the Low Carbon Hub group the cash last year, and it is due to be repaid by 2019.

The rest of the money needed to build Sandford Hydro came from a £2m loan from the Charity Bank and investment from Oxford residents.

The power plant is now due to start operating in the next four weeks.