Finally, after a year-long delay, the London Underground's all-night service is set to open this Friday - hurrah.

From 19 August, every weekend will see a 24-hour tube service on certain lines, with more to join later in the autumn.

The move was a huge win for London mayor Sadiq Khan, who said earlier this year that getting the service up and running was a priority:

"The Night Tube is absolutely vital to my plans to support and grow London's night-time economy - creating more jobs and opportunities for all Londoners."

What do we really know about the Night Tube? We've compiled everything you need to know:

The logistics:

The service begins on 19 August this year, with Central and Victoria lines.

Night Tubes will only operate on Friday and Saturdays between 12.30 and 06.00.

The Central line will operate between Ealing Broadway and Hainault.

The Northern line will run on the entire line but miss out the Mill Hill East and Bank branches.

The Piccadilly line will run between Cockfosters and Heathrow terminal Five.

The entire Jubilee line will run.

The entire Victoria line will run.

TfL predict the busiest stations will be Piccadilly Circus, Leicester Square, Waterloo, Victoria, Covent Garden, Brixton, Holborn, Oxford Circus, Stratford and North Greenwich.

An estimated 180,000 travellers will use the Tube during night opening hours.

The timings

Jubilee and Victoria trains will run on average every 10 minutes across all lines.

Central line trains will run every 10 minutes between White City and Leytonstone, and every 20 minutes between Ealing Broadway to White City and Leytonstone to Loughton or Hainault.There will be no service between North Acton and West Ruislip or Loughton and Epping or Woodford and Hainault.

Northern Line trains will run every 8 minutes between Morden and Camden Town and every 15 minutes from Camden Town to High Barnet and Edgware. There will be no service on the Mill Hill East or Bank branches of lines.

Picadilly line trains will run every 10 minutes between Cockfosters and Heathrow Terminal five - but there will be no service to Terminal four. There will be no service between Acton Town and Uxbridge.

The fares

Day travelcards can be used until 4.29am the next day, and standard off-peak fares will apply on all lines.

The safety

TfL have deployed 100 officers to be on hand during night services to ‘help customers travel with confidence’, and have assured customers that the same number of workers will be on shift as during the day.

Officers will be supported by British transport Police rapid response vehicles.

Sadiq Khan says that: "Keeping Londoners safe is my number one priority. The extra investment in British Transport Police officers will ensure that all Londoners using the night Tube feel safe, whether getting back from work or going out at the weekend with friends."

Londoners have mixed views about the service...

A YouGov survey revealed last year that 79% of us are happy with the announcement of a night tube service at weekends, one in three have revealed they would never use the service.

Why some are against it:

Confirmation of a 24-hour Tube service at weekends brought music to the ears of many Londoners who have cut short their weekend revelries in order to catch the last tube for the past 153 years.

But the Night Tube - originally set to open in September last year - was delayed because staff were unhappy about the shift and pay changes – despite having been offered a 2% pay rise and a £500 bonus at the time.

The predicted cost of the tube has risen to £17million with subsequent annual costs of £25 million.

Rail worker unions believe that it could bring unfair working hours and pay.

The RMT union maintains that there are still "major" unresolved issues surrounding working conditions - hence the unconfirmed date for all lines opening.

There will also be job cuts due to ticket office closures.

There are concerns among some surrounding the safety of women, and the increased likelihood of drunk people causing disorder or falling onto tracks.

Why it's a really great thing for London:

The Night Tube will benefit many people, from weekend shift-workers, to party-goers and those who don't feel comfortable on a rowdy night bus or forking out for an Uber. 

Late-night journeys home will be shortened by an average of 20 minutes.

The Night Tube will support almost 2,000 permanent jobs in London’s night-time economy.

Late night Tube journeys have increased at double the rate of daytime journeys since 2000.

It will boost London’s economy by £360 million over the next 30 years.

Estimated profits in the first year will be £8.3 million.

There will be a load of new trains.

Ten fun Tube facts:

1) The Victoria line was nearly called the Viking line (Victoria-King's Cross)

2) Approximately half a million mice live in the London Underground

3) Fewer than 10% of Tube stations are located south of the river

4) Jerry Springer was born at East Finchley station during WWII when his mother took shelter during the Blitz

5) Underground escalators travel the equivalent distance of going twice round the world, every week

6) During WWII part of the Piccadilly line was closed to be used as storage for British Museum artefacts.

7) It costs £500 per hour to film in the Tube, unless you have a crew of less than five

8) Covent Garden station is said to be haunted by the ghost of actor William Terriss, who was stabbed to death there in 1987.

9) The Jubilee line is the only one to connect with all others…it is also the most complained about line.

10) Sting and Paul McCartney have both busked in the Underground, in disguise. 

Images: Rex Features