Labour leader Jeremy Corbyn will address Welsh Labour delegates less than 24 hours after Carwyn Jones’s shock news he is to step down as first minister and Welsh Labour leader.

Mr Jones made the announcement on Saturday saying he had been through the “darkest of times” following the death of former minister Carl Sargeant.

He will step down in the autumn after nearly nine years in charge.

Mr Corbyn said he had led Welsh Labour to “unprecedented electoral success”.

The Labour leader is expected to use his speech in Llandudno to blame Prime Minister Theresa May for the Windrush immigration scandal.

It follows an outcry over Caribbean people who legally came to the UK decades ago as Commonwealth citizens who have lost jobs and homes or been threatened with deportation because they cannot prove their right to be here.

• Carwyn Jones to quit as first minister
• Harris elected Welsh Labour deputy leader
• Timeline: The death of Carl Sargeant

Finance Secretary Mark Drakeford, considered by many to be a front-runner for the job of first minister, said he was giving “serious consideration” to putting himself in the running following Mr Jones’s announcement.

Others, including Jeremy Miles, Alun Davies, Vaughan Gething and Huw Irranca-Davies, have declined to rule themselves out.

The first minister told the conference that his departure would give his family, his party and the country a “fresh start”.

Referring to his wife and family, Mr Jones told delegates: “I don’t think anyone can know what the last few months have been like – no one apart from Lisa and the kids.

“They have carried me through the darkest of times. I have asked too much of them at times. It’s time for me to think about what’s fair to them.”

Mr Jones has been under pressure since former communities secretary Mr Sargeant was found dead in November, four days after Mr Jones sacked him from the cabinet amid allegations of inappropriate conduct towards women.

On Friday, lawyers for Mr Sargeant’s son Jack – who succeeded him as AM for Alyn and Deeside – said the family was frustrated at delays to an independent inquiry into Mr Jones’s handling of the November reshuffle.

They also said Mr Jones’s own conduct had caused “considerable distress” to the family.

Responding to the first minister’s announcement, Jack Sargeant said: “Nothing changes. The inquiries are still relevant and should continue.”

Mr Corbyn paid tribute to Mr Jones’s record in office, saying: “Carwyn has led Welsh Labour to achieve unprecedented electoral success, forming two Labour Welsh Assembly governments.

“Over the last nine years he has stood up to Tory austerity and stood up for the people of Wales as a strong voice for devolution and democracy.”