Fourteen prison officers have been suspended after an inquiry uncovered the smuggling of drugs and mobile phones into one of Britain's oldest and most overcrowded jails.

The suspended staff members at Pentonville Prison in King's Cross, north London, were also accused of having "inappropriate relationships" with prisoners.

Senior officers from other London prisons will now investigate the alleged corruption at the 150-year-old jail.

"If any alleged or otherwise suspected criminal activity is uncovered, the relevant information will be passed to the police," a spokesman of the Prison Service said.

"I will not tolerate corruption of any sort," added the service's director general, Phil Wheatley.

Apart from criminal charges, corrupt officers would also face "the appropriate disciplinary action", he said.

Built in 1843, Pentonville Prison is certified to house 1,177 inmates, but routinely holds over 1,200 - often with two people in cells designed for one.

Two months ago a report by its own Independent Monitoring Board criticised the overcrowded jail as "unsuitable to house prisoners in the twenty-first century". Drugs and mobile phones were also discovered among the inmates.

On Monday the prison, which normally accepts up to 672 new prisoners a month, told the courts not to send any more convicts.

Pentonville has a total of 379 staff, of which 139 are on duty at any one time.

At least 1,000 of the 48,000 prison staff in England and Wales are corrupt, a leaked report of the Met police and the Prison Service's anti-corruption unit said two weeks ago. More than 500 officers had "inappropriate relationships" with inmates, it added.