They ran an extra four miles in a half-marathon – and all they’re getting is a lousy T-shirt.

Marathon runners at a previous Boston Marathon.

Marathon runners did an extra 4 miles in Bangkok. Image by Danielle Walquist Lynch / CC BY 2.0

The peace offering came after runners vented their anger on social media following Sunday’s extra-long Standard Chartered Bangkok Half-Marathon, which was mistakenly extended by almost seven kilometres (four miles).

An error by race officials along the route in the Thai capital meant participants ran 27.6 kilometres (17 miles), rather than the usual 21 kilometres (13 miles).

Some 6,000 runners took part in the race and everyone – even those who could not finish it – will get a special shirt to wear like a badge of pride, said Songkram Kraison, vice president of the Jogging Association of Thailand.

Mr Songkram said: “The T-shirt will say ‘Finisher of 27.6 km’. The shirts are meant to apologise and also to honour runners who ran in the longer version of the half-marathon.”

The Jogging Association of Thailand’s website posted a statement on Tuesday saying it will send out the shirts within 45 days.

The race looped through Bangkok’s historic district, past the Grand Palace, monuments and Buddhist temples, with half-marathon participants sharing the route with full-marathon runners until a specified turn-off.

That is where the error occurred, according to organisers, who said officials stationed along the route accidentally directed half-marathon runners to make a U-turn at the wrong spot, which added the extra miles.

“We deeply regret this unfortunate mistake,” the Jogging Association of Thailand said in an apology letter posted in Thai and English on websites and Facebook pages connected with the event. “We admit our mistake and would like to apologise.”

The T-shirt is meant to “express our admiration for your spirit in bravely overcoming the obstacles”, the letter said.

(Press Association)