The quartet's positions have been sealed following British Swimming's revision of its selection policy for the postponed Games, which are now scheduled to take place from July 23 to August 8 in 2021.

All four met the required qualifying times for their respective events at the 2019 World Aquatics Championships.

British Swimming had previously announced that the 2021 British Swimming Championships in April will act as the main selection meet for Tokyo 2020, but Peaty, Scott, Wilby and Greenbank have earned places at the Games regardless of their performances at the National Championships under a chance in policy.

British Swimming's decision to change its usual policy is due to the COVID-19 pandemic, which has disrupted the usual organisation of events.

"Limited competition opportunities in the last 12 months and the ongoing uncertainty around preparation for the April 2021 British Championships means we have had to adjust our usual framework for selection of our Tokyo Olympic team," said British Swimming national performance director Chris Spice.

"This has not been an easy task, however we have tried to give some certainty to a small number of high-level athletes in the event of even more national lockdowns, whilst at the same time keeping the British Championships as our main focus for our Tokyo Olympic selection."

The four swimmers will not be officially named in Britain's Olympic squad until June.

Peaty is the reigning world champion in the men's 50 metres and 100m breaststroke, and also holds the Olympic title in the latter from Rio 2016.

Wilby won silver in the 100m breaststroke behind Peaty at last year's World Championships in Gwangju, while Scott won bronze in the 200m freestyle and Greenbank won bronze in the 200m backstroke - all three winning their first individual world medals in South Korea.

Following selection at the British Championships, any remaining places on the team will be decided based on times achieved at four major events, including the 2021 European Championships in Budapest in May.