The prime minister says the plan "would be rejected by a significant margin" if MPs voted on it.
"Evil monster" Russell Bishop is found guilty of murdering two nine-year-old girls in 1986.
The victims' barrister says there is "overwhelming" evidence the service failed to prepare for the fire.
The pound falls to the lowest level against the dollar since June 2017 amid uncertainty over Brexit.
UK government provided £2.3m funding to support initiative countering Russian disinformation.