Organisers of the UK's major mass-participation events - including the London Marathon - have launched a campaign to help charities plug an expected £4bn income shortfall.
The 2.6 Challenge aims to get the public to come up with activities to compensate for the cancellation of events because of coronavirus.
It will launch on Sunday 26 April, the original date for the London Marathon.
The race was postponed until 4 October to limit the spread of coronavirus.
With so many mass-participation events called off - and many of those intending to take part doing so for charity - there are concerns about the knock-on effect that will have.
The London Marathon - the world's biggest annual one-day fundraising event - itself generated £66.4m for charities in 2019.
The 2.6 Challenge hopes to inspire people to create their own athletic activities based around the numbers 2.6 or 26, which trigger donations from themselves or others.
Hugh Brasher, event director of the London Marathon, told BBC Sport: "This is something the marathon is really passionate about and so are the rest of the mass participation sport organisers.
"As a group, we got together and we've been getting together on sustainability. With Covid-19 and what is going on, we pivoted to what could we do for charities. This is about both inspiring activity and inspiring fundraising across the UK.
"The activity would be within government guidelines on social distancing, so you can do it indoors or outdoors."
Nick Rusling, co-chair of the Mass Participation Sports Organisers group (MSO), said: “The 2.6 Challenge can be anything that works for you. You can run or walk 2.6 miles, 2.6km or for 26 minutes.
"You could do the same in your home or garden, go up and down the stairs 26 times, juggle for 2.6 minutes, do a 26 minute exercise class or get 26 people on a video call and do a 26 minute workout – anything you like.
"We want people to get active, have fun and raise money to help Save the UK’s Charities by giving money or raising funds for the charity close to your heart.”
While the race has been postponed, BBC Sport will bring you some of the magic and memories of the London Marathon regardless this April.
On Saturday 25 April, BBC One will show a special programme on world record-holder, Olympic champion and four-time London winner Eliud Kipchoge as the Kenyam explains how he became the first human to break the two-hour barrier. It begins at 13:15 BST.
On Sunday 26 April, the day the 40th edition of the race was due to take place, BBC One will look back at 1981's inaugural London Marathon from 14:00 BST. There will also be live text on the BBC Sport website from 10:00 BST drawing on more memories of the past and finding out how you are making up for the race's absence.