Volunteer mappers in the UK have described their “incredible” and “rewarding” experiences in lockdown helping to fight female genital mutilation (FGM) thousands of miles away in east Africa.

The Crowd2Map project has gained almost 3,000 new mappers since the beginning of March last year, bringing the total number to around 16,000 from across the globe.

Almost a third of the people working from their bedrooms and living rooms helping to plot millions of buildings on previously blank areas of Tanzania on OpenStreetMap are from the UK, said London-based project founder Janet Chapman.

Their work is used to help guide activists on the ground to girls at risk, and is thought to have helped save more than 3,000 girls there from FGM since Crowd2Map was set up in 2015.

FGM, the intentional altering or injuring of the female genitals for non-medical reasons, is against the law on under-18s in Tanzania but still happens in many villages.

Speaking ahead of this year’s International Day of Zero Tolerance for FGM on Saturday, Ms Chapman said it was “amazing” to see an upsurge in volunteers during the first lockdown.

Ms Chapman, who is also chairwoman of the Tanzania Development Trust (TDT), said many told her they were glad to have something meaningful to do during the pandemic.

She told the PA news agency: “It’s been amazing to see so many new mappers during lockdown.

“Many have told me that they are grateful for the opportunity to do something useful in these difficult times.

“Others have said they relish the chance to learn a new skill, and some find mapping soothing, even meditative.”

Catherine O’Farrell, 26, said she “needed more purpose” in lockdown while she was shielding with epilepsy and severe asthma.

The psychology graduate from Flintshire in North Wales said her volunteer efforts made her realise “a pandemic that shuts us away in our houses over here doesn’t end FGM”.

She said: “The first mapping sessions you do truly are incredible – taking a section on the map, finding and mapping all of the roads and buildings in a part of the world that’s so far away.

“Then you start to think about the people living in the buildings you map, the girls you will be helping.”

“When you’re mapping a building, to know that that’s going to help someone...it’s just super rewarding.”

Samantha Connolly-Boles got back into mapping early in the lockdown last year after having her first child.

The 34-year-old from Lanarkshire in Scotland, who previously worked in victim support for the British Transport Police, described it as an accessible and rewarding activity.

She said: “I can dip in and out when I want to.

“When you’re mapping a building, to know that that’s going to help someone find one of the girls that needs help, it’s just super rewarding.”

The sociable side in speaking to fellow volunteers online is an added bonus, she said.

“I’m going onto the forums more and having a chat with the other volunteers more than I would’ve done before (lockdown) I think,” she said.

“With being in the house all the time you do crave that communication and that connection.”

IT consultant Krishna Pavan Challa said the aim of his volunteer work is “to bring things to life” on the maps on the computer.

The 39-year-old father-of-two, who lives in Dartford, Kent, said: “We try to plot things on OpenStreetMap and bring them to life and then the real action, the tangible action happens with the field volunteers (in Tanzania).”

He said his seven-year-old daughter, Anika, had even got involved after asking what he was doing and saying she wanted to help.

He added: “I said it’s not a game, it’s something important that I am doing.

“She quickly picked it up on her own.

“She said she wanted to do it.”

Crowd2Map is holding an online mapathon on Saturday suitable for beginners as well as more experienced volunteers.