The organisers of the London Marathon have confirmed that runners will be encouraged to wear a black ribbon at the start of Sunday's race to honour victims of the attack on the Boston Marathon.
An email to runners this morning said:
"As a show of solidarity with our Boston friends, we would also like you to wear a black ribbon at Sunday's race.
You will have the opportunity to collect this ribbon when you register at the Expo to pick up your race number."
The email also said that a 30-second silence would observed at all three race starts and would be signalled by a whistle.