Sadiq Khan on Tuesday rejected calls for the Silvertown and Blackwall tunnel tolls to be scrapped as a public consultation on the proposed levies entered its final day.Under draft plans published in July, motorists will be charged £4 to use either tunnel at peak times, and £1.50 off peak and at weekends. There will be no charge between 10pm and 6am on any day of the week.The charges will be imposed from Spring next year – a precise date has yet to be announced - when the Silvertown tunnel opens.At present, the Blackwall tunnel, which is used by about 100,000 motorists a day, is free, and has been since it opened in 1897.Mr Khan, speaking to the Standard ahead of the close of the Transport for London consultation on Tuesday night, said the tolls were needed to pay back the £2.2bn cost of constructing and operating the Silvertown tunnel under a PFI scheme.