Putin needs to do very little.
All that will happen is the usual expelling of diplomats on both sides (one of the oddest & most fruitless exercises) and some sabre rattling by the UK.
What will not change (
which Jeremy Corbyn has demanded) is the fact the UK is used to launder the ill-gotten gains of the Russian Oligarchs who have looted the wealth of Russia.
Not one single one of these Oligarchs prospered without being a confederate of Putin and those who survive remain basically in partnership with him.
The fact Conservative MPs dismiss the £Millions in donations from the the so-called Russian / UK citizens is ridiculous and they know it.
Putin and Russia now have the Conservatives in their pocket which partly explains the desperate attacks from the right-wing media on Corbyn attempting to paint him as a "Russian spy" in a classic
"look over there" attempt at diversion.
Those who have followed Putin's rise from the beginning (me) including security agencies around the world have noted the pattern.
Putin has successfully compromised so many powerful people in his rise to be the autocratic ruler of Russia.
The long term Putin plan is the break-up of the EU and nobbling of NATO. Blind Freddy can see Putin's fingerprints everywhere from Brexit to Donald Trump's victory and the seducing of the Tories.
Few people have bothered to read any of the biographies of Vlad Putin when he's the major power force in the world.
Many totally underestimated Putin's incredible cunning and skill at manipulation firstly as a top KGB agent and then as Moscow mayor and finally as Prime Minster which was a planned to be an 18 month stop-gap by Boris Yeltsin's co-horts but which backfired spectacularly.
Each and every living billionaire Oligarch ( including the UK "citizens" like the owner of
The Evening Standard & Independent newspapers ..football clubs etc etc) aided and conspired with Putin and are his allies. Try and end that and you have an accident.."commit suicide" etc.
Few in the West seem to understand the complex nature of the majority of Russian people who admire Putin's ruthless nature and success.
Like the Chinese president (and as Donald Trump would so love to be) Vladimir Putin is the ruler of Russia for life.
I've read 3 Putin (all come from different angles but reach the same conclusions)..the best was this- he's one of the most fascinating men on the planet at present.