Thousands of marathon runners and their supporters face disruption to journeys as they attempt to reach the capital next weekend around a 24-hour national train strike.
Railway workers on Network Rail and at 14 train operating companies will walk out on Saturday, October 1st in a row over job security, pay and working conditions. They are to be joined on the same day by members of train drivers union ASLEF - which is likely to mean train services across the country grind to a standstill.
The London Marathon takes place on Sunday, October 2 - the morning after the first of October's planned 24-hour walkouts. A second strike is planned by ASLEF drivers for Wednesday, October 5.
Last year 40,000 people took on the course in person - with a similar number signing up to run the same distance virtually.
After months of training and preparation, and after disruption and changes to previous races because of Covid-19, the announcement that fresh strikes - postponed because of the Queen's death - are taking place just hours before the starting gun is fired on the race is likely to strike a blow to organisers, runners and spectators.
The running show at exhibition centre Excel - in which participants must collect their event pack and all-important running number - is also happening on all four days before Sunday's race, meaning that runners signed up to take on the 26.2 city course are also likely to see their final preparations for the event also impacted by the industrial action.
Those trying to get to the capital to watch or take part in the marathon are being told to plan ahead and pay close attention to possible changes to transport services on the day they set off.
But what are the options for reaching the capital if train services are cancelled or slow to return to normal?
Will any trains run?
The train strike itself is a 24-hour walkout happening from midnight on Friday, September 30 until midnight on Saturday, October 1.
But as with previous train strikes this summer, services are expected to begin being wound down much earlier on the Friday evening in preparation for the walkout at the strike of midnight, while on Sunday morning - the day of the marathon itself - there are already warnings that trains may not be up and running as early as they ordinarily would.
This is because safety checks that would normally be done overnight need completing before services can run and trains could be out of place as a result of the sudden day-long pause.
The Rail Delivery Group says the industry is doing its best to work around the upcoming strike days, but passengers are being warned that some parts of the country will have little or no rail services and the message for those with the marathon in mind, is likely to be not to rely solely on the trains to guarantee getting into London.
Further details about capacity and more exact timetables are expected in the coming days but train operator Southeastern, which runs services between Kent and the capital says it expects no trains to run on the Saturday while the start time for Sunday morning services so far remain unclear.
A spokesperson said: "It is regrettable, but we do not expect to be able to run any trains during the upcoming strike action. We are already working hard to get services back to normal once this period ends.
"We know the importance of keeping our customers up to date and will continue to publish more information as soon as we are able."
Driving to the capital
With thousands likely to be forced into their cars to make the journey to London, National Highways is asking drivers to plan their journeys carefully and run some basic checks on their vehicles ahead of time to avoid the risk of a breakdown.
The organisation, which operates and maintains 4,300 miles of road, says it's ready with additional traffic officers and control room staff to manage any extra congestion, particularly on routes it is responsible for in and around the capital.
While August's train strikes saw no significant increase in incidents or congestion on the roads - compared to the same time the previous week - traffic officers are braced for more people travelling by car on this occasion because the London Marathon is taking place the day after the first planned strike.
Drivers are being reminded that live traffic information can be found via TrafficEngland.com, by calling the National Highways Customer Contact Centre on 0300 123 5000 or by following National Highways on Twitter.
Parking operator NCP says it can help make people's journey to the marathon 'hassle free' whether they are watching or taking part.
It has a dedicated London Marathon parking web page which lists the nearest car parks for people to book - whether they're looking for a space closest to the start or finish and depending on where they are travelling from. Spaces can be pre-booked in advance and more details can be found here.
Drivers are also being reminded that they can find parking wherever and whenever they need it using the JustPark app, which enables you to reserve a space at more than 45,000 locations.
London shopping centres Westfield London, near Shepherds Bush, and Westfield Stratford City in the east of the capital opposite the Olympic Park, also have thousands of car parking spaces likely to be popular with those in the capital over the first weekend of October because of how close they are to other transport services into the city.
Other popular parking spots in or close to London for those travelling by car are likely to include Stanmore station car park in Middlesex for those coming from the north of the UK, because of its hundreds of spaces and close links to London's public transport, and the O2 at Greenwich is likely to be another firm choice among those coming by car from the south.
The entertainment complex on the river, formerly known as the Millennium Dome, has 2,100 car parking spaces, is minutes from North Greenwich tube station, the bus station and Thames Clipper stops while those needing to pick up their running numbers from the Excel centre on the other side of the river can use the Emirates Cable Cars also on the same site, to cross the Thames.
With runners coming from across the world to take on London's course, demand for hotels and other places to stay is always high over the weekend of the marathon - even without the added complication of a train strike.
An internet search of the Premier Inn website for one night between Saturday, October 1 and Sunday, October 2 found just one option - in Tooting - with all other London branches across the capital currently listed as being sold out.
Fellow budget-chain Travelodge still had some rooms available in and around London for the night before the marathon, with those closest to the start lines in Greenwich starting at £224 for two adults on a room-only basis.
Public transport in London
With strike action mostly affecting train staff and drivers, it is expected that most public transport services in London such as buses and the London Underground will be able to run both before and on the day of the London Marathon.
While runners may not be able to use train services to make it into London early enough on the day of the event to join their running wave, according to the official London Marathon runners' guide, services on the Docklands Light Railway will start on Sunday, October 2 at 5.30am from Tower Gateaway and Lewisham and from 7am from Bank and other DLR routes to enable people already in the city to make it to the start in Greenwich on time.
Travelling by boat
Those forced towards London by car as a result of the train strikes may find a ride along the River Thames a preferable option when it comes to getting themselves to where they need to be.
Uber Boat by Thames Clippers stops at 24 piers along the Thames between Barking Riverside Pier in the East and Putney Pier in the West and services run from early in the morning until late at night 7 days a week.
Like the tube, the river is divided into zones: West, Central and East and tickets must be valid for all the zones you travel through.
Marathon organisers say the river bus runs every 20 minutes from central London to Greenwich Pier and from here it's just a short walk to the course start areas.