The Welsh government has stolen a march on Boris Johnson by announcing a three-week extension to its coronavirus lockdown and making modest adjustments, including allowing outdoor exercise more than once a day and plans to reopen libraries. The first minister, Mark Drakeford, insisted the lockdown needed to stay but said “very cautious” changes would come into force. He anticipated that “broadly” similar changes would be announced by the prime minister. Drakeford emphasised that he remained keen on the four nations of the UK working as one over the lifting of restrictions and said the new rules would come into force on Monday so Wales moved in step with the rest of the UK. Asked if he was happy with how the UK government was working with his administration, he said: “It has been a bit of a fits-and-starts experience.” The announcement came as Scotland’s first minister, Nicola Sturgeon, said that she believed “all four nations now accept there may be differences in pace of how we do these things because the level of the virus is at different stages”, although she expected variation with England’s upcoming new guidance to be minor. She plans to confirm over the weekend whether to allow more daily exercise, but said garden centres will remain closed for the time being and emphasised the “stay at home” message. Sturgeon said the rate of transmission of the coronavirus – the so-called ‘R’ number – is currently between 0.7 and 1 in Scotland, but closer to 1 than 0.7. Drakeford said the ‘R’ number was believed to be 0.8 in Wales. He said if this figure remained constant, it was estimated there would be about 800 more deaths between now and August. If it went up to 1.1, there could be 7,200 deaths. Speaking at the Welsh government’s press conference in Cardiff on Friday, he said: “We must not lose the progress we have made. All of us must continue to work from home whenever we can. All of us must only travel when absolutely necessary. All of us must continue to observe the 2-metre social distancing, and wash our hands and take those basic hygiene precautions. The margins are so small.” But he said that from Monday, people will be allowed to exercise more than once a day, while not travelling “a significant distance” from home. Garden centres will be allowed to reopen, provided they can ensure the 2-metre physical distancing rule is followed. And councils will begin to work on plans to safely reopen libraries and municipal recycling centres. Drakeford’s intervention came 48 hours before the prime minister is due to announce possible changes to the rules in England. The first minister was also due to address the Welsh nation at 5.55pm on Friday. Despite signs of tension between Wales and Westminster, Drakeford said he wanted to “move in step with the other nations of the United Kingdom”. Asked if he was attempting to restrain Johnson by announcing the modest changes, he said: “It’s not an attempt to place restraints on anybody else. I spoke with the prime minister yesterday. The prime minister emphasised his wish to move in the most careful and cautious way. “While it will be for the prime minister to decide the steps that will be taken in England in adjusting regulations, I don’t believe you will see anywhere in the UK anything other than the most modest of immediate changes broadly of the sort that I have proposed making in Wales.” On his relationship with the UK government, Drakeford said: “When we have discussions with UK ministers they work well. They are open and engaged. What I’ve tried to argue for is a more reliable pattern of that engagement. We tend to get it, it doesn’t happen for a while, then it resumes again. “When we have it, it is good. It would be better from my point of view if it had a regular reliable pattern so we could maximise the desire of all four governments across the UK to work closer together. The more we talk the more we understand each other.” Drakeford denied the changes he announced risked sending out mixed messages. “For most people in Wales, staying at home remains the right thing to do,” he said. He called on people not to travel to beaches or beauty spots over the bank holiday weekend. “I want to make it very clear Wales remains in lockdown. Nothing has changed. A journey to the beach or mountains is not essential travel. The police are ready and will stop people. People will be sent home.”