"The plan was in the advanced but not imminent stage and plotters had been tracked by spy agencies for some time", said Sky's foreign affairs editor, Tim Marshall.
Marshall said the planned attacks would have been similar to the commando-style raids carried out in Mumbai (Indian city) by Pakistan-based gunmen in 2008, killed 166 people.
He said the European plot had been "severely disrupted" following intelligence sharing between Britain, France, Germany and the US.
It is not known whether the attackers are already in Europe.
When the terror plan came to light, the US military began helping its European allies by trying to kill the leaders behind the plot in Pakistan's Waziristan region.
"I am led to believe a number of these attacks were designed against the leadership of this particular plot, which had an Al Qaeda and possibly some sort of Taliban connection projecting into Europe," Marshall said.
"And they have killed several of the leaders- which is why the terror threat has not risen," Marshall added.