London was plunged into travel chaos today as the first of two 24-hour Underground strikes began, causing major disruption to Tube services across the capital.Members of the Rail, Maritime and Transport union (RMT) walked out from midnight and will strike again for 24 hours on Thursday over proposals for a four-day week.The two sides met for five hours yesterday for last-ditch talks with the assistance of conciliation service Acas, but this failed to resolve the dispute over the working week.Tube services were affected early this morning with the Circle and Waterloo & City lines fully suspended at 7am as RMT members mounted picket lines outside stations.The Bakerloo, Central, Metropolitan, Northern and Piccadilly were all part suspended; while the District, Hammersmith & City, Jubilee and Victoria were running with delays.The suspensions caused chaos for commuters and other travellers this morning, with many forced to queue for buses outside major travel hubs in the pouring rain.Footfall in key London areas dropped compared to a normal Tuesday morning – with the City down 16 per cent, Westminster down 11 per cent, King's Cross down 8 per cent and the West End down 6 per cent, according to O2's anonymised mobile data. Transport for London (TfL) warned passengers of disruption to journeys throughout the strike action period and said service levels will vary across the Tube network.On both days, there will be limited service before 6.30am and customers were told to complete their journeys by 9pm. Normal service is expected tomorrow and on Friday.An Elizabeth line station is packed in London today as the capital is hit by further Tube strikes Heavy rain falls outside Farringdon station in London today as the capital endures a Tube strike Passengers at London Liverpool Street station this morning as the capital endures a Tube strike Commuters queue for a bus outside Vauxhall station in London during today's Tube strike Commuters queue to get on a bus outside London Victoria station in the rain this morningLondon Overground, Elizabeth line, Docklands Light Railway, buses and trams will continue operating during the strike periods but are expected to be far busier.The RMT - Britain's largest specialist transport trade union - is opposed to a new four-day week because of the impact on the length of shifts and other issues.An RMT spokesperson said: 'Despite our best efforts in Acas talks, TfL have failed to provide assurances on our members' deeply held concerns around fatigue, reduced flexibility, shift lengths and the impact these proposals could have in a safety-critical role like Tube driving.'We remain available for meaningful talks, but strike action will now go ahead.' Transport for London Tube services at 7am Fully suspended: Circle, Waterloo & CityPart suspended: Bakerloo, Central, Metropolitan, Northern, PiccadillyRunning with delays: District, Hammersmith & City, Jubilee, VictoriaSee more Daily Mail on Google - save us as a Preferred Source A TfL spokesperson said: 'It is bitterly disappointing that despite five hours of meetings with the RMT at Acas and repeated assurances that the four-day working week proposals will remain voluntary, RMT has chosen to continue with its disruptive strike action. We will do all we can to provide as much service as possible during this action.'A spokesperson for London Mayor Sir Sadiq Khan said: 'Nobody wants to see strike action – which has a serious impact on Londoners, businesses and commuters.'The Mayor continues to urge the RMT and TfL to get around the table to resolve this matter, so we can avoid further disruption and keep London moving.'The strikes are officially taking place from 0.01am until 11.59pm today and again on Thursday.Ed Richardson from the BusinessLDN group said: 'These strikes are yet again set to make it more difficult for Londoners and visitors to make journeys around the city.'Although the city did not come to a complete standstill during the April strikes, with the Overground and Elizabeth line running and many Londoners turning to other modes of transport like e-bikes and buses.'But for many businesses that rely on people visiting in person, the impact of these strikes – whether they go ahead or are called off at the last-minute – will have already been felt through cancelled bookings and people changing their plans. Commuters queue for a bus outside Vauxhall station in London during today's Tube strike The RMT picket line at the main Arnos Grove depot in North London this morning Commuters walk across Vauxhall Bridge in the heavy rain this morning during the Tube strike A woman looks at a sign listing service disruption details at Hammersmith Tube station today Tube trains parked at the London Underground's Boston Manor depot in West London today Passengers packed onto a South Western Railway train towards London Waterloo this morning A woman stands outside closed gates at Boston Manor station in West London this morning Commuters wait at Surbiton station in South West London during the Tube strike today'We urge both sides to reach a sustainable agreement to put an end to the damaging uncertainty hanging over businesses and London's economy.'Michael Kill, chief executive of the Night Time Industries Association (NTIA), also said: 'Today's Tube strike action is another major setback for London's hospitality, leisure and night-time economy.'Businesses across the capital rely heavily on office workers, commuters, visitors and tourists travelling into central London, and any disruption to the transport network has an immediate and measurable impact on footfall, trade and consumer confidence.'For many hospitality businesses, particularly independent operators, the loss of customers caused by transport disruption is simply unaffordable in the current economic climate.'Venues are already facing rising operating costs, increased employment costs and continued pressure on consumer spending. Another day of significantly reduced trade only adds to those challenges.'Commuters and other travellers were also hit by disruption to South Western Railway services this morning.The operator said that due to heavy rain flooding the railway between Fulwell and Shepperton all lines were blocked. Passengers were told that train services running to and from these stations may be cancelled or delayed.Services were also disrupted because of a 'precarious' tree between Weybridge and Hersham, in Surrey, which led to some lines towards Surbiton being blocked.The RMT held its last Tube strike during the week of April 20, during which TfL ran around half of all its services.TfL said that on every day of that industrial action, more than half of normal demand was observed on the Tube, while Friday April 24, the final day of action, the network saw 94 per cent of normal demand.Another RMT strike planned to begin on May 18 was called off at the last-minute after the union claimed TfL had 'shifted its position', allowing it to 'explore our members' concerns' about new rosters.Last week, the Daily Mail revealed militant union barons were plotting a 'winter of discontent' in a bid to get inflation-busting pay hikes .Union sources said barons were gearing up for national action which could shut down hospitals, schools and the railways after Labour made it easier to call strikes.The RMT is threatening a UK-wide strike campaign to get above-inflation pay rises - although the union is not expected to launch any ballots until after the summer.Eddie Dempsey, the union's boss, wrote to all his members in April saying he was demanding blanket pay rises higher than the retail price index (RPI) level of inflation with no-strings attached.When he wrote to members RPI was more than 4 per cent, while the officially preferred consumer price index rate was at 3.3 per cent. The latter has since dropped to 2.8 per cent but experts say it could rise above 4 per cent again later this year.