HI Clifford, I`m Afraid I do`nt agree with Cheeky, I believe that London is a good course for a P.B., I`ve done 11 Londons ,my first was 2hours 55 mins, my best was 2 hours 40 mins, my last was 3hours 30 mins, 3 months after a cartilage opperation,I never ran it again after that,but I honestly believe the finish on the Mall, rather than on the bridge,makes for a better faster finish.I`m now 65 years of age and just into my 3rd week back training after a 5 year lay off,my pace at the moment is 7.6 m.p.m, so maby next year I might get the chance to make it an even dozen in london, good luck, run your own race,and run it even.