This all could have been sorted 5 years ago!
Our parliament voted not to intervene, by the labour party (lefties )
It's funny how they protest outside downing street against it yet they don't protest against the some 400,000 people that have died!
The reason Russia is involved is because they wanted a navel and air base in the Mediterranean which they now have.
They don't give a hoot about Syria!
The only part I disagree with you about, is your fantasy that this "could have been sorted 5 years ago!"
What do you imagine would have been done five years ago, that would have changed here and now? Britain was never going to invade Syria and occupy it, even if all of your anti-labor parties united to take control of Parliament.
The factors that are affecting what is going on now, are only different than five years back, in that we now have Trump sending occasional missiles in.
Unfortunately, aside from the missiles, Trump wants to hand the entire mess over to Russia.
Look at what happened in Iraq by comparison. Saddam Hussein used chemical weapons and others on his own people repeatedly, and it didn't stop until he was physically overthrown and executed. And all THAT invasion accomplished, was to put Iran firmly into the position of the most powerful state in the region, with no serious opponents.
Not a very clever "solution."