The outgoing Welsh first minister, Mark Drakeford, says he hopes his time in power will be remembered for “radical” measures such as clamping down on second home ownership in Welsh language heartlands and introducing the much-reviled 20mph speed limit. Drakeford, who announced last week he would be stepping down, criticised the UK Conservative government for not taking the devolved nations more seriously and said a Labour administration in Westminster was desperately needed to fix “broken Britain”. Speaking to the Guardian in the first minister’s art deco office in Cathays Park, Cardiff, Drakeford revealed he had thought about leaving office this December exactly five years after he became first minister, but put it off until March because of Wales’s financial difficulties. “I decided not to do that because I knew by then how difficult setting a budget for next year was going to be. I didn’t think it would be sensible to do that against the backdrop of a leadership election, which has its own currents.” His government’s draft budget, published on Monday, includes wide-ranging cuts across areas from the environment to the arts in order to protect the NHS and council services. Drakeford accepted that getting the budget through the Senedd in the new year would be challenging. “The budget is full of very difficult decisions we would rather we didn’t have to make. There is a big political job to be done in the spring term.” Another important task will be appearing at the Welsh module of the Covid inquiry, which begins in late February. Giving evidence there while still in post felt the right thing to do, he said. “It is something about respect for the families.” When he became first minister in 2018, Drakeford promised to do radical things. He conceded that the Covid pandemic got in the way of some ambitions. “But I think, I hope, people will see this as a period when we did some of those challenging and radical things.” One of the first was to scrap the M4 relief road, which supporters believed would relieve congestion on the motorway and boost the economy but critics said would cause huge environmental damage, not least to the precious Gwent Levels. “The conventional thing would have been to give it the go-ahead. I felt that if we were to be serious about the challenges facing us, [the] changing climate, the burning platform we are creating around the globe, we couldn’t go on doing things in the way we had.” Drakeford suggested one of the most radical things his regime had done was to give local authorities the power to use planning laws to stop local people selling up to would-be second homeowners. “That is a significant intrusion into the way people normally live their lives but it’s part of our determination to stop parts of Wales becoming social deserts where nobody actually lives. It’s not popular with some people.” The first minister said he did not believe another of his government’s controversial moves, the introduction of a Wales-wide 20mph limit for most built-up areas, was as radical as the reaction to it suggested. He compared the 20mph limit with the introduction of a smoking ban in enclosed public places, which Wales did before England. “I remember what a huge issue that was, but who would go back to that now? You run into people who are attached to the status quo. I think in time people will say, what was the fuss about 20mph?” Other innovations coming soon include changes to council tax. “We’re the only part of the UK to reform the most regressive form of taxation and we will reform the school year. It’s only taken 150 years but we are going to do it.” Drakeford was a fierce critic of Boris Johnson’s approach to Covid – and to Wales. He said he did not feel the same “overt hostility”’ to Wales from Rishi Sunak. But he said the UK government continued to make grabs for power in Wales, breaking the Sewel convention that is supposed to stop Westminster legislating on devolved matters, and Sunak did not seem interested in Wales. “Rishi Sunak is not the aggressive figure of his predecessors [Johnson and Liz Truss] but nothing much has changed.” Drakeford expressed sadness that there had been no meeting all year between the prime minister and the first ministers. “It tells you everything you need to know about the lack of interest.” The first minister, who is from the left of the party, was a supporter of Jeremy Corbyn but he will get behind Keir Starmer and defends the UK Labour leader’s recent praise of Margaret Thatcher, a hated figure in much of Wales. “It’s important to capture the point he was really making: some prime ministers have decisively altered the direction of the country. He wasn’t endorsing the direction she took. Margaret Thatcher is a figure who is not admired in Wales, the harm she did to so many communities lives on in people’s memories. “Keir wasn’t praising Thatcher’s record. He was saying he wants to be a prime minister who marks a decisive change of direction and, my goodness, don’t we need that? “We badly need someone who will put our country back on track. The idea that Britain is broken is the daily experience of many people in this country. The things they thought they could rely on no longer work in the way they previously took for granted.” Drakeford said he would be “fully engaged” in his remaining three months as first minister. “Then I’ll be a member of the Senedd for another two years.” He said he was glad when it was announced he was stepping down. “You inevitably have some mixed feelings. I’ve been very fortunate. I’ve been in the middle of devolution since the beginning, which is more or less a quarter of a century. There will be days when I miss it and there will be days when I won’t miss it at all.”