Re: @AC ... @Jimmy Page He needs to show that he had reasonable cause to jump bail
"They can sneak him out into an embassy car, so it can't be searched."
The embassy does not have an attached garage (it's upstairs), and there's no diplomatic immunity between the embassy and the car (it passes public property). They know the ways in and out and will be suspicious of ANY goings from that place. And they can't unilaterally designate him a courier because the UK holds rejection power under the Diplomatic Privileges Act.