Commuters in the City of London will be contending with a crowd of 5,500 runners in addition to dodging long lines of people waiting to get on London buses during the Tube strike.
About 200 extra buses will take to the roads to ease the burden of the strike on commuters. In the evening on 9 July routes will be held up travelling through the City by the Standard Chartered Great City Race. Diversions will be in place from 6.30pm until 8.30pm.
"We have employed more than 100 additional stewards to assist the general public on the evening of the race," said Hugh Brasher, event director for London Marathon Events Ltd. "These additional stewards will join our existing teams to help the public at the pedestrian crossing points and to direct public to diverted bus services along the route."
The event organiser held a meeting on 8 July to make plans around the Tube strike.
Brasher said the group considered rescheduling the 2015 run. But he said: "However, since this is an annual event that is in its 11th year, we believe that Londoners who work or live in the City have an understanding of the road closures and bus diversions that are put in place for the event. It was not a decision taken lightly."
The group is working with the City of London Police but officers said they would not increase their presence at the race to direct traffic. "It's stewards that deal with controlling crowds," said a City of London Police spokesperson.
Every year, the race sees law firms, banks and other agencies in the capital raise hundreds of thousands of pounds for charity. For 2015, the race will donate money to train eye care workers in developing countries.
The race will affect bus routes 4, 8, 11, 21, 23, 25, 26, 43, 56, 76, 100, 133, 141, 153, 172, 214, 242, 271, 388, and 521.
Roads affected include City Road, Finsbury Pavement, Chiswell Street, Beech Street, Aldersgate Street, Montague Street, King Edward Street, Newgate Street, St Martins Le Grand, Gresham Street, Wood Street, Cheapside, Poultry, Princes Street, Lothbury, Bartholomew Lane, Threadneedle Street, Old Broad Street, London Wall and Moorgate.