Tooting policeman Ben Whitby had an outstanding run in Sunday’s Flora London Marathon, where he took the silver medal in both the UK and England men’s championship races.

Whitby, 31, took more than four minutes off his previous best time, set in Berlin last September, in finishing 16th overall.

Whitby, who trains regularly with Herne Hill Harriers at Tooting Bec track, was aiming for two hours, 16 minutes and was on target as he went through the halfway point just past Tower Bridge in 1:08:14.

During the second half of the race, he began to suffer from spasms and cramps in his legs and was forced to slow down by about 10 seconds a mile.

He managed to keep going to finish in 2:18:14, more than 12 minutes faster than he managed on his London debut last year and eclipsing his previous best of 2:22:37 in finishing 23rd in Berlin last September.

“I am a bit frustrated as it was not as quick as I wanted but I am really pleased with my performance,” said Whitby.

“The conditions were fine and, in places, compared with Berlin, the crowd was vast. I really enjoyed the experience.”

While the elite runners set off at a suicidal sub-two hour pace, Whitby was not drawn into their battle.

“I knew what I had to do and I kept to it. After halfway my legs felt dead and I suffered from cramp. But to achieve a personal best is very satisfying.”

Whitby will now take a break with a view to running a marathon in the autumn.

“I might do a 10km race on the track in the summer,” he said.

As he was no longer training for the marathon, Whitby thought Monday night was an opportune moment to have a crack at kayaking on the Thames at Westminster.

“I have never done it before so I thought I’d have a go. I really enjoyed it but I have got no plans to switch sports and take it up seriously,” said the former British number one steeplechaser.

John McFarlane, who finished 21st in 2:20:44, led Thames Hare & Hounds to the men’s team title.

Other members of the team were Andy Weir, who was fifth veteran in 2:29:13, and Julian Rendall (2:31:54).

Herne Hill’s Ben Paviour smashed his personal best as he took more than 10 minutes off his pevious best time with 2:29:17 in finishing 51st.

First Belgrave finisher, but running in Australian colours, was Martin Dent, who was 14th in 2:15:24, just 38 seconds outside his lifetime best.

OTHER CLUB RUNNERS 65 Will Cockerell (Belgrave) 2:31.15, 80 Ben Reynolds (Thames Hare & Hounds) 2:33.05, 85 Mike Halman (Hercules Wimbledon) 2:33.57, 89 Hussein Ahmed (Hercules Wimbledon) 2:34.19, 97 Andreas Groth (Ranelagh) 2:34.44, 106 David Freeman (Tadworth) 2:35.21.

Hercules Wimbledon’s James Trapmore, also making his marathon debut, was 111th in 2:36:00.

Epsom-based Dan Taylor, 35, ran two hours, 58 minutes, on his marathon debut to earn automatic qualification for next year.