Meeting: Hate preacher Abu Qatada (left) with car bomb terrorist Yasser Al-Sirri

Abu Qatada's bail conditions were under review last night after security experts said allowing the hate preacher to associate with a convicted terrorist made a 'mockery' of the rules.

Home Office officials are investigating the Daily Mail's exclusive picture showing Qatada - dubbed 'Osama Bin Laden's ambassador in Europe' - strolling through London with fellow fanatic Yasser Al-Sirri.

Incredibly, Al-Sirri, who was convicted in Egypt and sentenced to death in absentia for his part in a 1993 car bomb attack - was not included on a list of more than 20 extremists with whom the preacher of hate is banned from associating.

Whitehall sources said the Home Office is reviewing the evidence to see whether there are grounds to ask the courts to add Al-Sirri to the list.

They will also investigate claims that Qatada, whose bail conditions forbid the use of a mobile phone, was using Al-Sirri to pass on messages.

The Mail's picture, first published on Saturday, appeared to show Al-Sirri talking into a mobile after listening to an instruction from Qatada, who is under a 22-hour curfew. 

Describing the bail conditions as 'nonsense', Tory MP Patrick Mercer, a security adviser to the Prime Minister, said: 'Yasser Al-Sirri is a dangerous individual. The fact he is allowed to associate with Abu Qatada makes a mockery of Qatada's bail conditions.

'The Home Office has got to stop its tinkering and ensure that proper checks and measures are in place to protect the public from extremists. That includes adding Al-Sirri to the list of those Qatada cannot associate with.'

Al-Sirri, 46, is a former member of Egypt's Islamic Jihad. In 1993, the group attempted to assassinate the then Egyptian prime minister using a car bomb outside a girls' school. The attack failed, but a 12-year-old girl was killed in the blast.

Al-Sirri had left Egypt the previous year and claimed he had no direct role in the attack.

Although Egypt has repeatedly called for his extradition, Britain has refused. Home Office officials are now trying to establish whether Al-Sirri was considered and discounted from their list, or if there was an oversight.

A spokesman for the department said: 'The list can be reviewed and we will seek the permission of the court to add or remove individuals as appropriate.' However, proving Qatada was using Al-Sirri to communicate via mobile phone - in breach of his bail terms - is likely to prove difficult, as it would need evidence of what was said.

The spokesman added: 'Any evidence of an alleged breach of Special Immigration Appeals Commission bail conditions will be investigated and appropriate action will be taken.'

Yesterday, the think tank Centre for Social Cohesion, formerly part of Civitas, which identified Al-Sirri from the photograph, said: 'Although Al-Sirri has never been convicted in a UK court, there is ample evidence to suggest he has been involved in radical Islamic movements since the early 1990s.

'During this time, he has been closely associated with leading extremists both in the UK and abroad. That Abu Qatada is allowed freely to meet with such an individual - and to apparently use him to pass on messages - indicates serious flaws in Qatada's bail conditions.'

Qatada was granted bail by the courts earlier this year, after they ruled it would be a breach of human rights law to return the hate preacher to his native Jordan.

The judges said that - even though the Home Office had an agreement that Qatada would not be harmed - some of the evidence used against him may have been obtained by torture.

The Home Office is appealing to the House of Lords, with the case expected to be heard later this year. If ministers lose, Qatada cannot be held on bail, but is likely to be placed under a less- strict control order.