The London Living Wage will rise to £9.40 an hour next year as the cost of living in the nation’s capital continues to spiral.

The mayor of London, Boris Johnson, announced that the voluntary rate would rise to 25p, which will be higher than the government is mandating. The National Living Wage outside London is increasing by 40p an hour to £8.25.

Chancellor George Osborne announced the National Living Wage of £7.20 earlier in the year. It will rise further to £9 per hour by 2020. The number of firms paying the Living Wage is on the rise in the capital and currently stands at 724, up from 429 at the start of the year.

Johnson announced the rate in an Oliver Bonas store, an up market fashion chain. The mayor said in his announcement that Londoner’s have to receive a fair share of the proceeds of the capital’s success.