TUC chief Frances O'Grady has told Daybreak that "if we bring the railways back under public control, there would be more money to invest for the future."
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The Labour leader did not say whether he would maintain Britain's nuclear deterrent programme.
Ukip leader Paul Nuttall also said he would want to get rid of Sharia courts.
Over 40,000 people picked up their packs to take part in the annual marathon in the capital.