The Queen and other members of the Royal family have had their security stepped up because police believe British air strikes on Syria have increased the risk of a terrorist attempt on their lives.

Royal sources said the security measures were enhanced from the moment Parliament voted in favour of bombing Syria on Wednesday, The Telegraph reported on Saturday.

All senior members of the Royal family are affected, though Prince Harry is seen as particularly vulnerable because of his active military service in Afghanistan.

A police source said: “Now they’ve had the Syria vote we’ll have to review his security as everyone becomes more of a target.”

According to reports in the US, European intelligence agencies have specific information that the Islamic State of Iraq and the Levant (Isil) has decided that Britain will be the next target of an attack.

Wednesday’s parliamentary vote, in which MPs voted by a majority of 174 to extend air strikes against Isil targets from Iraq into Syria, increased the concerns of intelligence agencies that British jihadis who have been trained in Syria have been told to return home and carry out an attack.

The Royal family are seen as the ultimate targets for Isil in this country because of the unparalleled worldwide publicity an attack on them would generate.

All Royal visits at home and abroad are now under review to decide whether they are necessary, sensible or feasible in the light of the increased terrorist threat.

The Duke and Duchess of Cambridge are due to visit India in the spring, and while there is no suggestion that visit will be cancelled, their protection team is likely to demand that local police impose a ring of steel around them wherever they go, with the 2008 Mumbai attacks still fresh in the memory.

Sources: MENA