Dozens of London Marathon runners had their finish line dreams dashed on Sunday after railway line problems meant they missed competing in the race.

Issues on the First Capital Connect Thameslink line caused by Network Rail track improvements which went awry caused around an hour of delays last weekend between Harpenden and Radlett.

Louise McPhee’s son Angus managed to narrowly get to the starting line on time, but he ended up losing his chance to warm up prior to the 26.2 mile run.

As a result his running time was significantly affected and the 21-year-old finished in five hours 11 minutes compared to his time last year of four hours 15 minutes.

His mother Louise, of Redbourn, said: “We went to catch the 10 to 8 train along with a whole other lot of supporters. We caught exactly the same train last year and we were at the start line at quarter past 10. But this year we ended up sitting outside Radlett station for 45 minutes.”

She added that when they went back to the station to complain, the supervisor on duty said a lot of the runners didn’t actually get to run: “I just felt so gutted for all these people who had raised huge amounts of money for charity.

“They have given up their time and their money – for some people not to have run is just awful.”

A Network Rail spokeswoman said the company apologised for the service disruption which was due to a broken down machine supporting track relaying.