The government was not lied to.
They went to war over the invasion of Belgium and Britain's treaty obligations.
That was not a lie.
The people supported that, and most historians think they were right to.
No-one is lying to the historians.

Margaret Macmillan said, "Britain certainly thought it had legitimate reasons for going in, and I think it did," she says. "

The myth you all desperately cling to is discredited and debunked.
Rubbished.