"Edmund Fitton-Brown, Senior Advisor to the Counter Extremism Project and former Ambassador of the UK to Yemen, told MailOnline this evening 'it could all very easily spiral out of control'.

'In essence, I think Iran and Israel would both prefer to avoid escalation out of control,' he said.

'But Iran (and Hezbollah) both want to be seen to respond to the Israeli assassinations.

'Calibrating such responses in such a way as to save face and yet avoid escalation gets more difficult with each successive round of skirmishing.

'The US is also part of this picture, seeking both to restrain Israel and to deter Iran,' he said."