Islamist extremists are allegedly planning at least two further terror attacks in London in the near future.

Anti-terror police have stepped up surveillance to monitor the new “active” plots, which are believed to be inspired by Isis or a resurgent al-Qaeda, according to the Sunday Times.

Those involved in planning the fresh wave of attacks are not connected to the two plots that were foiled last week, the newspaper reported.

"There are another two plots being closely watched," the Sunday Times quoted a senior anti-terrorism official at Scotland Yard as saying.

Met officers smashed two suspected terror plots within hours of each other in the capital on Thursday.

Armed police wrestled an alleged knifeman, 27, to the ground in Westminster in the afternoon before detaining six people, including a 16-year-old boy, in raids linked to a family home in Willesden, north-west London.

On Sunday, police were continuing to quiz the seven people who were arrested in the two separate counter-terror operations.

A woman in her 20s who was shot during the raid is being held under police guard in hospital, where her condition is described as serious but stable.

She is expected to be arrested when her condition improves.

Security in London has been heightened following the Westminster terror attack, in which Khalid Masood ploughed into pedestrians along Westminster Bridge before stabbing PC Keith Palmer to death at the gates of Parliament.

The current terrorism threat level is severe, meaning an attack is highly likely.

It was revealed last month that security services have thwarted 13 potential attacks in less than four years.