Prison Security: Howard rejects new calls for jails inquiry: Gun find and escape raise doubts over treatment of Britain's most dangerous prisoners. Heather Mills reports

THE DISCOVERY of a gun and ammunition in Durham prison yesterday - the third such incident there this year - has again called into question security in prisons housing some of the country's most dangerous criminals.

Michael Howard, the Home Secretary, ordered an inquiry but declined Labour's call for a full review of prison security. He is already embarrassed by the armed IRA breakout from the special secure unit at Whitemoor and, yesterday, solicitors representing the IRA men fuelled that embarrassment by lodging complaints claiming their clients were assaulted after being recaptured.

A police spokesman said yesterday that 'a senior Cambridgeshire police officer is investigating'.

The Prison Officers' Association immediately seized upon the Durham incident to further underline its claim that the top category prisoners were living in conditions of lax security, because of staff shortages. David Evans, secretary of the POA, said full 'rub-down' searches of visitors were no longer being carried out as a matter of course.

After details of security breaches at Whitemoor and the wide scope of privileges granted to those in the secure units, the Home Secretary has also been accused of running a policy of 'appeasment' towards high-risk prisoners which threatened security.

But speaking yesterday on BBC Radio 4, he angrily denied the claim. 'I do not for one moment accept there is anything remotely resembling appeasement. I utterly reject that.' High-security prisoners faced much greater restrictions than people in other areas, he said. The whole question of privileges in prisons was under review.

A man and a woman were charged last night after the hand gun and six rounds of live ammunition were seized at the top security jail.

Yesterday, Simon Bowman, an armed robber who has made two escapes in four years, and is serving 12 years, was transferred from Durham to the special secure unit at Full Sutton, York. He had only been back behind bars since May after his second escape two months earlier from Preston hospital, Lancashire.

Tony Blair, the Labour leader, said there was growing cause for concern about prison security. 'The thought that security arrangements may be more lax for high-security prisoners will strike people as absolutely extraordinary,' he said. 'In the light of the incidents over the past few days it would be folly for us not to investigate this very clearly and there needs to be a proper review of security arrangements.'

But Derek Lewis, the beleaguered director of the Prison Service, said the fact that three attempts to get guns into Durham had all been foiled showed that security at the prison was working.

The man and woman arrested at Durham yesterday had passed through a security screen and were then stopped and searched by detectives and prison staff. Six live rounds of ammunition and a small amount of cannabis were recovered.

A three-hour search in the jail led to the discovery of all the component parts of a small .22 handgun in the prison's segregation unit.

Ray Mitchell, the prison governor, told a news conference at the jail: 'There has certainly been no easing of our security measures and there has been no reduction in the manning of the unit that was involved in that particular incident.'

Two prisoners with convictions for violence were still on the run after five inmates escaped from Thorp Arch prison near Wetherby, West Yorkshire.