That step had been due to take place on 21 June, but is now being put back until 19 July - the day after The Open is set to finish in Kent.
In a statement, the R&A said: “Following this evening’s announcement by the Prime Minister to delay the move to Step 4 in the UK Government’s roadmap, we would like to reassure fans that we will shortly be able to confirm our arrangements for The 149th Open being held at Royal St George’s from 11-18 July.
“We are in active discussions with the UK Government and public health authorities regarding capacity levels for the Championship and hope to provide a definitive update for all ticket holders and hospitality guests in the next few days. We would like to thank all fans for their patience and support.”
In delivering an update last month on plans for the Claret Jug event, which was cancelled last year due to the pandemic, R&A chief executive Martin Slumbers revealed the St Andrews-based organisation had been working on three different set-up scenarios.
He said the range for the number of spectators within those was between 25-75 per cent of full capacity, which would have been 40,000 per day at the Kent venue,
A strictly limited number of fans are set to be in attendance in the Aberdeen Standard Investments Scottish Open at The Renaissance Club the previous week.