Britain’s armed forces are making contingency plans for a possible military strike against the Assad regime to deter the “abhorrent” use of chemical weapons, Downing Street has confirmed.

Amid expectations that David Cameron will announce that parliament is to be recalled later this week to discuss the Syrian crisis, No 10 indicated that Britain and the US would not be bound by the findings of the UN weapons team which inspected the Damascus suburb hit in the chemical attack.

In a sign of the increased pace of activity, the prime minister’s spokesman said plans for a military strike were under way. The spokesman said: “I am not going to get into details on any specifics. All I would say is it is reasonable to assume that our armed forces are making contingency plans.”

Downing Street said any military action would be designed to act as a deterrent against the future use of chemical weapons by the Assad regime and by others around the world. The prime minister’s spokesman said any action would be fully in line with international law.