Warning: spoilers follow

Loosing Jo last week to a televised terrorist campaign, the team are dealing with their loss in their own way. Ruth and Harry are thrusting and parrying around each other, speaking but not really ‘talking' to each other, Ros is having sleepless nights and Lucas falls into the arms of his CIA counterpart Sarah Caulfield (or Nancy Drew as Ros calls her) in a scene that can only really be described as ‘tits and tats'.

Having the ability to grieve and linger on Jo's demise is short lived as the Grid team investigate a riot at immigration centre which is something they would usually not do. However, the instigator of the riot is Oleg Darshavin, the man who held captive and tortured Lucas for the entire time he was kept imprisoned in Russia.

Meeting up with Oleg, Lucas (who for some reason spends a lot of this episode in a state of undress, making my wife very happy) is told that he has information he wants to trade for a new life, and for the cost of £1 million and a fake British passport he will provide Lucas with information to do with a major terrorist plot that has been planned.

Undecided whether to trust his former captor, Lucas plays both sides, trying to sort out his conflict in this situation with his loyalty to his team and ‘stockholm syndrome' for this former torturer, with trust being a major issue on both sides.

While Lucas and Oleg use the streets of London as a playground for a merry chase of deception and classic spy games, the rest of the team are using what information they have gained to try and clarify if the threat Oleg discussed is real, using both technology and pure guile to establish if the proposed Sudan based terrorist plot is real.

With Ros in the field and Ruth and Tariq unravelling the trail of clues back at HQ, there is also the added problem of both the Russians and Americans adding unknown x-factors to the investigation, and the problem of who is playing who means that Harry is, once again, in the position to ‘trust no-one' as more details emerge of the New World Order plot that the home secretary mentioned to him last week.

With Sarah causing Lucas to make some difficult decision (and getting kidnapped by Oleg in the process), the team manage to get all the loose ends, clues and tip-offs needed to find that, indeed, the thread is real and that the location and terrorist bomb threat is in central London, and as Ros is on the scene trying to defuse the situation, Lucas finally confronts Oleg with both Sarah and thousands of innocent lives in the balance.

While this is a more personal episode, there are some huge implications set up and executed for the rest of the series, and while it might seem a waste of momentum to re-tread the imprisonment of Lucas from the beginning of last season, all the flashbacks, dabs of information and the entire setup are all relevant as it not only shows Lucas' state of mind but also the changing landscape of loyalties and priorities as Oleg's former bosses and Lucas' former prison wardens in the FSB are now allies in a new war that the team of the Grid have only just scratched the surface of.

With the notion to trust nobody we are teased at what the coming problems might be, as we are teased with information about a secret conference in Switzerland called the ‘Basel Conference'. It seems that even Oleg knows something is brewing and that even those whom you thought were on the ‘good' side have their own agenda and that even the most loyal or operatives may not be who they say there are.

With a jaw dropping ending that just adds to the conspiracy, we fade to black with the tantalising trailer for next week as Ruth, Harry, Ros and Lucas delve a little deeper into the Basel Conference and a potentially key player finally shows her true colours.

Once again, edge of your seat stuff. Spooks continues to be one of the best shows the Beeb currently offers.

Read our review of episode 3 here.