Possible byelection would be the first of this parliament and will pose a big challenge for Labour

Here are comments from some of the other UK political parties on the third anniversary of the invastion of Ukraine.

From Ed Davey, the Lib Dem leader

For three years, the brave Ukrainian people have heroically defended their country against Putin’s war machine. Now we face an era-defining moment which will determine the future of our continent for generations to come.

Now, more than ever, we must stand firmly in support of our Ukranian friends, resist Trump’s alarming attempts at a stitch up with Putin and work with our European neighbours to defend freedom and democracy.

Across the world today, people will be standing in solidarity with Ukraine. Yes, Russia started the war and yes, Ukraine is a democracy with an elected President. These basic facts need restating loud and clear because US President Donald Trump has chosen to buy into and amplify the lies and disinformation of the Russian state.

Vladimir Putin is a dangerous tyrant. It is deeply worrying that President Trump is now joining him in sowing division and chaos, and undermining the rule of law.

Today we remember the sacrifices made by the people of Ukraine to resist the illegal invasion by Russia. We stand in solidarity to protect the independence and territorial integrity of Ukraine. We welcome and hold dear the Ukrainian people who have come to Scotland.

Today, on the third anniversary of Russia’s inhumane and illegal invasion of Ukraine, Plaid Cymru reiterates our unwavering support for Ukraine’s security and its sovereignty. We stand in solidarity with the people of Ukraine.

We are deeply concerned about the decision by the President of the United States to exclude Ukraine from discussions whilst engaging directly with Russia. Decisions about Ukraine’s future must include Ukraine itself. We also believe it is vital that the UK does not capitulate to continued Russian aggression.