Britain’s biggest train fleet refurbishment will give passengers “a much-improved travel experience”, according to Avanti West Coast.

The operator said the 56th and final modernised Pendolino train has returned to service.

The £117 million refurbishment project was carried out by manufacturer Alstom at its plant in Widnes, Cheshire.

This has involved the installation of 25,000 new seats, a redesigned shop, additional luggage space and better on-board information screens.

Other changes include upgraded lighting, refurbished toilets and new carpets.

All 35 Pendolinos with 11 carriages have had one first class carriage converted to standard class.

The tilting, electric Pendolinos transformed long-distance rail travel in Britain when they were introduced on the West Coast Main Line by then-operator Virgin Trains in July 2002.

Earlier this month Avanti West Coast began rolling out its new Evero trains, which are replacing diesel-powered Voyagers.

The operator’s Evero fleet will eventually consist of 10 electric trains and 13 bi-modes which can be powered by electricity or diesel.

Avanti West Coast managing director Andy Mellors said: “The refurbished Pendolinos, together with our new Evero fleet, are a key part of our mission to transform rail travel for our customers on the west coast route.

“The Pendolino is an iconic train, and now even better than before, offering customers a much-improved travel experience, with innovation and sustainability at its heart.”

Alstom’s UK managing director for services, Peter Broadley, said: “Alstom’s successful completion of the UK’s biggest ever fleet upgrade demonstrates our commitment to enhancing the journey experience for fare-paying passengers while, at the same time, supporting the growth of sustainable rail travel in the UK.

“This milestone highlights the dedication and expertise of our team at Widnes.

“They have worked tirelessly in partnership with colleagues at Avanti West Coast, Angel Trains and our wider UK supply chain to elevate the interior refurbishment of rolling stock to another level.

“We are immensely proud to see the entire Alstom-built Pendolino fleet returning to service in peak condition.”

Rolling stock asset management company Angel Trains financed the programme.

Labour has said it will urgently consider stripping Avanti West Coast of its train operating contract if it wins the General Election.

In a recent interview on Sky News, shadow transport secretary Louise Haigh accused the company of providing “woeful service” on the West Coast Main Line.

Office of Rail and Road figures show Avanti West Coast had the third worst reliability of all operators in Britain in the year to the end of March, with the equivalent of one in 15 trains (6.9%) cancelled.