An intruder said to have been armed with a knife came close to breaking into the Israeli embassy in London last night.

Scotland Yard swooped to arrest a 33-year-old man who had scaled the wall of the building on Kensington’s Palace Green, one of the most secure roads in Britain.

A source said the man was wearing a traditional Palestinian keffiyeh headscarf, was wielding a knife and had moved close enough to attack staff.

‘From what I know someone was trying to climb into the building up the walls of the embassy and they were armed with a weapon,’ they said.

‘The weapon was a knife of some sort, he was definitely armed and was wearing a keffiyeh.

‘The people in the embassy were told to stay away from the building for a few hours.

‘He managed to get very close to where staff members were, so naturally people were absolutely terrified.

‘From my understanding he was on the walls and he got arrested by police.

‘They need to investigate exactly how someone was able to get that close – it is one of the most secure roads in the country and should be one of the most secure buildings.

‘He got in between a space in between the building and Palace Green, so could have got to someone to attack them certainly.’

A Metropolitan Police spokesman said: ‘Officers at the Embassy of Israel, W8, became aware at 17:56hrs on Monday, 28 April of a man attempting to gain unauthorised access to the grounds of the building.

‘Officers prevented the man from entering, identifying a number of offences as he was detained.

‘The 33-year-old man was arrested and has been taken to custody for questioning.’

The embassy has been contacted for comment.