BRITAIN'S security services have foiled a terrorist plot in the last three weeks, it has emerged. 

David Cameron revealed how there had been seven plots in the last few months; one more than was revealed by Andrew Parker, the head of MI5, as recently as October 28.

The PM's spokesman explained that there had been seven terror plots foiled "in the last year" ie during the last 12 months.

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When it was pointed out that given Mr Parker had said at the end of October there had been six plots, this then meant one had been foiled in just the past three weeks, the spokesman replied: "Yes. He set that out at that point...It's definitely seven."

Earlier, the Prime Minister again repeated that the UK faced a "generational struggle" against so-called Islamic State, announcing an additional 1900 personnel are to be taken on the by the security services to combat the increased terror threat. Details of the new funding will be announced on Monday in the UK Government's security and defence spending review. Meantime, spending on airport security is to be doubled to nearly £20 million.

"I have been aware of these cells operating in Syria that are radicalising people in our own country, potentially sending people back to carry out attacks. Our security services have stopped seven attacks in the last six months albeit on a smaller scale(to the Paris attack)," explained Mr Cameron.

Three weeks ago, the MI5 chief said in a speech: "With our partners, we have thwarted six attempts at terrorist attacks in the UK in the last year and several plots overseas."

The PM made clear that Britain, which alongside other EU countries, observed a one minute's silence today out of respect for those killed in the Paris massacre, stood shoulder to shoulder with France.

"Those attacks in Paris, that could have happened in Belgium, that could have happened in Denmark, it could have happened in Sweden, it could happen here. We stand in total solidarity with France after the appalling attacks in Paris," declared Mr Cameron, who is due to give a speech later today that will touch on security matters .