With bar-free windows and river views, the first inmate will arrive at £253million at the mega-jail in Wellingborough, Northamptonshire next January after months of construction.

The mega prison in Wellingborough, Northamptonshire, will hold 1,680 inmates

The windows will not have bars and some will have a river view

The blocks have been built in cross shapes with jail designers ditching the usual K-shaped formation of prison housing blocks

New photos show a light and airy double room and single room at Her Majesty’s Prison Five Wells, with brightly coloured walls and unobstructed views over the beautiful River Nene and a fishing lake.

It will hold up to 1,680 inmates - making it England's biggest jail - and has just been structurally finished, with works due to be completed by October.

HMP Five Wells tweeted: “Been a busy day on site today but took the opportunity to grab a couple of pics for you.

One of a double room, there are 84 in total, and one of the single rooms with the FANTASTIC barless window …albeit not the best view at present #bestprisonever.”

The category C jail is seen as a flagship example of the Government’s aim to create a “modern, efficient prison estate that is fit for the future” and will have a clear focus on rehabilitating offenders.

It has been built on the site of the former HMP Wellingborough site, which closed in 2012, and held a maximum of 650 adult male inmates.

The first inmate will arrive at the privately run jail on January 8 next year

The rooms have brightly coloured walls

The jail will have a clear focus on rehabilitating offenders

The prison build has been handled by Kier group, using pre-cast components containing recycled materials and the roof is covered with solar panels.

New aerial photos also show the landscaped grounds, which include a horticultural area and four football pitches, where prisoners can exercise.

The jail designers have ditched the usual K-shaped formation of prison housing blocks and instead used seven staggered cross-shaped buildings.

The K-block style has been favoured since Victorian times, with the idea that a single prison officer could be placed in the centre of the radial arms of corridors and survey all the cells quickly.

The new cross-shaped buildings mean the corridors are broken up into smaller zones, rather than miles of long corridors, which will enable prison staff to have more direct contact with prisoners.

The buildings have been arranged around landscaped courtyards, with the cross-shaped design offering a better use of outside space for sports and gardening facilities.

There will be one central hub for education, vocational training and social facilities.

The first inmate will be taken to the prison on January 8 next year.