Justice secretary Chris Grayling has denied there is an overcrowding crisis in prisons, despite the most recent figures which showed Bure Prison had room for just one more inmate before it reached its maximum.

The prison population figures for May also showed Norwich Prison was nine prisoners below its 769 operational capacity, just six months after the last inmates of Blundeston Prison, near Lowestoft, left.

Labour's Waveney parliamentary candidate Bob Blizzard said the statistics and warnings showed the folly of closing the Suffolk site, and if the prison has not been sold before the general election, he would push for it to be reopened.

'There has been pressure on prison places for years. The idea that you can close prisons and not end up having a crisis is fanciful,' he added.

The figures come after chief inspector of prisons Nick Hardwick said at the weekend that he was 'very concerned' about the impact of a hot summer, with more prisoners having to share cells.

Mr Hardwick said ministers must find significantly more resources or cut the number being put behind bars to avoid 'huge tensions'.

The prisons watchdog has warned that a 'political and policy failure' has led to more inmates killing themselves or getting deliberately sent to punishment blocks to escape crowded conditions.

During an urgent question in the House of Commons, shadow justice secretary Sadiq Khan derided his opposite number for his 'complacency', and accused him of keeping MPs in the dark about the costs of providing extra places and rehiring prison staff who were previously made redundant.

The Government has ordered dozens of prisons to take 440 extra offenders between them to deal with the unexpected squeeze on places, which Mr Grayling partly blamed on the increase in convictions for historic sex abuse.

He said: 'We do not have a prison overcrowding crisis. Today's prison population is 85,359. This is against total usable operational capacity of 86,421, which means we have more than 1,000 spare places across the prison estate.

'We will also by next April have opened an additional 2,000 places. This includes four new house blocks which will start to open from the autumn. We also have a number of additional reserve capabilities to cope with unexpected pressures.'

The Justice Secretary also announced the creation of a reserve pool of staff made up of ex-prison workers to cover shortfalls.

HMP Blundeston, a category C training prison near Lowestoft, transferred its 500 male inmates to other jails over three months - mainly to other prisons in the region and closed in December.