Was it just coincidence that Tahir Mahmood went on stage?

Question

In episode 3 of “Bodyguard,” Tahir Mahmood steps onto stage at St. Mary’s college as the Home Secretary is speaking and the two of them, plus others, are blown up by a bomb. In the next episode we discover that the stage had a weight trigger and that his arrival set it off. This heavily implies that whoever asked him to go on stage was affiliated with those who planted the bomb.

We know that Mahmood was sent on stage by advisor Rob Macdonald as part of a scheme, together with other members of the home secretary’s staff, to embarrass her. The audience knows that some of the people in on this scheme have been plotting with the U.K. security services. This, together with interference in video recordings of the event, characteristic of the security services, implicates the security services in the assassination.

In the final episode it is revealed that the bomb had been set by members of an organized crime gang who had gotten the explosives from an Islamic terrorist. A senior member of the police force had been helping them by leaking information. So, were the security services involved? If so, why? If not, who got Mahmood to go up on the stage? Was it just coincidence that he went up there at the right time?

Answer 1

It is a coincidence

There are at least three conspiracies going on in Bodyguard (see this answer: https://movies.stackexchange.com/a/92741/134). Until the final resolution in the final episode, this is far from obvious.

Tahir's presence on the stage was a result of the political conspiracy to discredit the Home Secretary (by getting her to make dubious claims in her speech) which is mostly unrelated to the attempts to kill her. That is why Tahir was there. And, possibly, why MI5 wiped the tapes.

We don't really know (if memory serves) how the bomb was triggered. From memory the trigger mechanism was speculation not certainty (and for a while that speculation had the bomb in the briefcase). Whatever way it was triggered, it was clearly planted by the criminal conspiracy aided by corrupt police. They were the only people who really needed the Home Secretary dead.

The MI5 conspiracy wasn't about killing anyone. Initially they worked with the home secretary to undermine the prime minister and (possibly) switched sides when the Home Secretary didn't follow their advice. They didn't need to kill her because of this, but the clever plotting allowed the audience to speculate that they might by withholding key information from the viewers. Hence the confusion.

Answer 2

In the course of the action we learn that the only "islamic" bomb attack was the one targeted at school. All others were plotted by crime AND senior member of police AND secret service. So the scheme for that particular one goes as:

• Luke Aitkens plant the bomb
• MI5 learns about that and decide they will kill two birds with one stone. One being removing Home Secretary, second not being involved "personally" in the assassination
• via the vice to they involve MacDonald further removing them from suspicion by shifting it at least two stages away (one being MacDonald, second being terrorists).

Aitkens don't learn about Mi5 involvement as he only wanted to kill HS and he probably didn't learned the bomb did off because of outside help. Mi5 involvement is seen as they are the ones who removed recording and they were the ones responsible for checking the college for threats. They planned the thing to look like the bomb was in the suitcase.