An Edinburgh-based runner in the Boston marathon has spoken of her shock and sadness at the explosions.

Rosie Allister, 33, a former Edinburgh University student who is now deputy director of Edinburgh Samaritans and chairwoman of Vet Helpline, crossed the finish line around 30 minutes before the blastss occurred.

“I’m stunned. It’s so hard to take in. Of the 30 marathons I’ve run around the world, Boston yesterday was the best supported race anywhere I have run,” she said.

“As a runner it’s so humbling and inspiring that people you’ve never met before come out to support an event like this in the way that people did in Boston yesterday.

“Mass participation running events like marathons are about bringing people together, celebrating life and the achievements of people you love and those of people you have never met, and often remembering loved ones or raising money for good causes.

“The juxtaposition with the terrible events at one of the busiest possible parts of the entire race route is so hard to comprehend.”

The Boston marathon was the first leg in Ms Allister’s attempt to run 247 miles in a fortnight to raise money for the two charities she works for.

She has already raised more than £300 and the news of the explosions led to more donations.

Anna and David Thomas gave £10 via an online fundraising page and wrote: “Glad you weren’t caught up in the Boston explosions, praying for those who were. We think you’re a bit mad but the charities sound good. Hope you stay safe and well the next couple of weeks”.

Ms Allister remains undeterred by the explosions and will be on the London marathon’s starting line this weekend. “I’m due to be running the London marathon on Sunday and will be wearing my Boston finisher shirt and remembering those affected by this tragedy,” she said.

Nigel Holl,  chief executive of scottishathletics, said: "Last night sent a chill through us all as we watched the TV pictures.

"Every marathon is always a great celebration of human achievement, and the endeavours of those who ran to help their fellow runners and supporters, not to mention the efforts of the runners who competed as far as they were able, should inspire us all way beyond our love of athletics and sport.

"We send our best wishes to every member of the athletics family affected – athlete, spectator, official, family member, or fan, and trust that all the Scottish participants and their family members return safely."