Queen Elizabeth II reigned for 70 yearsHorse racing was halted on Thursday following the death of Her Majesty Queen Elizabeth II, while Friday's play in cricket's Test match between England and South Africa was called off.
All Friday's race meetings in Britain have also been cancelled, along with the same day's Rachael Heyhoe Flint Trophy cricket fixtures.
The second day of the PGA Championship golf on Friday will not take place.
The English Football League has also postponed its two games on Friday.
All English and Northern Irish football and all professional Scottish football has been postponed this weekend as a mark of respect following the death of Queen Elizabeth II.
It is scheduled to be the opening weekend of the Women's Super League and the Premiership Rugby season, while the Great North Run is due to take place on Sunday.
The Irish FA has announced that all football in Northern Ireland scheduled for this weekend will not take place.
The government's national mourning guidance states cancelling or postponing sports fixtures is not obligatory and "at the discretion of individual organisations", including on the day of the state funeral.
On the day of the funeral, the guidance suggests events could be rescheduled so that they do not clash with the timings of the service and that organisers could hold a period of silence or play the National Anthem at events, with players wearing black armbands.
Queen Elizabeth II, the UK's longest-serving monarch, died aged 96, after reigning for 70 years.
Following the announcement, the Southwell horse racing meeting was halted after the second race, and Chelmsford after the fourth race.
The British Horseracing Authority is likely to take a decision on when horse racing will resume on Friday.
Play was also abandoned at the BMW PGA Championship at Wentworth.
"Out of respect for Her Majesty and the Royal Family, play has been suspended at the BMW PGA Championship at Wentworth Club for the remainder of Thursday and flags at Wentworth Club will be lowered to half-mast," said a European Tour Group statement.
"Furthermore, no play will take place at the BMW PGA Championship on Friday and the golf course and practice facilities will be closed."
Organisers say they are hopeful of restarting the tournament at some stage over the weekend but will "review protocol guidance from Buckingham Palace in addition to aligning with what other major sporting events in the UK are doing".
In football, Manchester United said their game against Real Sociedad in the Europa League went ahead "following direction from the Football Association and Uefa".
West Ham's game against FCSB in the Europa Conference League was also played.
The Scottish Championship game on Friday between Cove Rangers and Dundee has been postponed.
Cycling's Tour of Britain has cancelled its final three stages in Gloucestershire, Dorset and the Isle of Wight, with Spain's Gonzalo Serrano given the race victory after keeping his overall lead on Thursday's fifth stage.
"This decision has been taken in consultation with stakeholders and partners in light of operational circumstances, including the understandable reassignment of police resource at this time," said a statement.
"The Tour of Britain organisation, alongside the teams, riders and officials involved in the event, send their deepest condolences to the Royal Family at this sad time."
In rugby union, Northampton abandoned their Premiership Rugby Cup clash against Saracens scheduled for Thursday evening.
Scotland women's Test international against Spain on Sunday has been called off and Scottish Rugby has also postponed all domestic competitive games this weekend as a mark of respect.
Friday's weigh-in for the women's world boxing title fight between Savannah Marshall and Claressa Shields will take place behind closed doors.
Promoters Boxxer are expected to issue a statement later on the status of the bout, which is scheduled to take place at the O2 in London on Saturday.
Formula 1 is planning a minute's silence with all teams prior to practice on Friday for the Italian Grand Prix, with the race weekend to proceed as planned.
At the US Open tennis in New York, organisers said "to commemorate the passing of Queen Elizabeth II" there would be "a moment of silence prior to the start of the first women's semi-final match between Ons Jabeur and Caroline Garcia".
