The UK government has imposed sanctions on hundreds of Russian parliamentarians as part of its response to the war in Ukraine.
386 MPs who voted to recognise two rebel-held areas of eastern Ukraine as independent last month have been hit by asset freezes and UK travel bans.
The UK said their recognition of Luhansk and Donetsk gave Russia a “pretext” for its subsequent invasion.
The US and the European Union had already announced similar sanctions.
The UK signalled it would impose sanctions of its own last month, but more time was needed to pass new legislation before it could happen.
The latest announcement means 400 out of the Duma’s 450 members are now subject to British sanctions, the UK government added.
The sanctions are directed at members of the Duma – the lower house of the Russian parliament – and will also prevent them from conducting business in the UK.
Foreign Secretary Liz Truss said the UK was targeting “those complicit in Putin’s illegal invasion of Ukraine and those who support this barbaric war”.
“We will not let up the pressure and will continue to tighten the screw on the Russian economy through sanctions,” she added.
The move follows sanctions on Russian banks, companies and oligarchs in response to Russia’s invasion of Ukraine last month.
On Thursday the UK announced sanctions on a further seven Russian oligarchs, including Chelsea FC owner Roman Abramovich.
The UK government says it means 18 Russian oligarchs, worth a combined £30bn, have been sanctioned since the Russian invasion began.