The importance of language in times of war again. You said this :
" Dont you believe 20 terror plots were prevented by counter terrorism?"
The Article you linked says this :
"MI5 has tracked more than twenty potentially lethal Iran-backed plots in just the one year since I last stood at this podium."
You added the word "terror".
I showed in posts above, with evidence, that these 20 plots, in so far as can be established, are mostly plots against Iranian dissidents in the UK. And abhorrent as that is, they were not terror plots. Your average Joan or John popping to the shops in Milton Keynes is not in danger of being blown up by the Iranian Government as you are alluding to when you insert the word "terror" into what was said.
And as @Notonthestairs says, the article mentions Russia an lot. Above Iran. It also mentions China a fair amount. And this line, at the top:
"But the aggregate scale of the terrorist threat remains huge. And the range of what’s coming at us – from terrorists holding poisonous Islamist, Extreme Right Wing or other ideologies - just keeps growing."
Yes people believe what the UK security services say. We hear what they say and understand it. Countries such as Russia, Iran and China are out to get their own dissidents that the UK have granted asylum and protection to. Extremists influenced by ISIS (Sunni) plot and do Bomb attacks. And note this "Extreme Right Wing or other ideologies"
All threats need to be taken seriously, no matter where from, And the security services do a great job. They especially do a great job protecting those people who are seeking or have been granted asylum. Those are the people these other states want to harm.
We hear what MI5 say. We believe what they say. But we are not changing what they say to try to justify a war.