Organisers claim they face "significant and unjustifiable barriers" from several councils around Britain because of the COVID-19 pandemic and have appealed to Johnson for help.

The five kilometres events were suspended in March 2020 as coronavirus took a hold.

They were due to resume on June 5 but got put back to June 26, with that date now in doubt too, with speculation mounting that the latest easing of restrictions in the UK will be delayed.

"Despite the Government's best efforts, parkrun finds itself trapped," it said.

Parkrun is a collection of 5km events for walkers, runners and volunteers that take place every Saturday morning, having been started in London in 2004 and which has now grown to more than 2,000 locations in 22 countries.

Events regularly take place at a range of general locations including parks, stately homes, forests, rivers, lakes, reservoirs, beaches, promenades, prisons and nature reserves.

World Athletics President Sebastian Coe is among those to have backed parkrun's appeal to Johnson.

Double Olympic gold medallist Coe has described prkrun as "one of the nation's greatest public health initiatives".

"We are deemed both legal and safe to return yet cannot do so because of uncoordinated and often unwarranted blockages by a number of local authorities who do not understand nor recognise the national framework," continued the parkrun letter.

"We are a small charity and as a Board we are fearful for our future.

"We need your help if we are to find a way through the added bureaucracy.

"It is clear that we need a significant intervention from the top of Government to convince a few councils that their actions are inappropriate, and that pakrun should be allowed to continue to benefit the mental and physical health of local communities in a safe and responsible manner."