Services on a major section of London's £19billion Elizabeth line have been suspended because of a stubborn SWAN.
Passengers on board trains reported being told the bird was blocking part of the route.
Transport for London's (TfL) website stated there are no services between Heathrow Airport in west London and Abbey Wood in south-east London - via the centre of the capital - due to "an obstruction on the track".
It added that there are "severe delays" on the rest of the line.
National Rail Enquiries said there are "animals on the railway".
The incident was first reported at 12.56pm on Thursday.
The line remained closed more than two hours later.
Have you been affected by the hold up? Let us know at webnews@mirror.co.uk
Passengers reported being held on trains - which do not have toilets - for up to hour due to a swan on the tracks at Paddington.
One Twitter user wrote: "I have been trapped on the Elizabeth line for an hour because of a swan on the line."
Another posted: "You are an absolute shambles @TfL. I cannot believe you closed the entire Elizabeth line for a swan on the tracks.
"Has nobody been on the shooing course. How hard is it to move a swan?"
The Elizabeth line stretches from Reading in Berkshire and Heathrow Airport to Shenfield in Essex and Abbey Wood.
It opened in May 2022 at an estimated cost of £18.9 billion.
All of the swans in England are owned by King Charles III.
According to the official Royal Family website, the Crown has held the right to claim ownership of all unmarked mute swans swimming in open waters across the country since the 12th Century.
Historically, this legislation was created because swans were eaten as a prized food at banquets and feasts. Valuable rights of ownership were granted by the monarch to a select few.
But today, swans are no longer eaten and are a protected species.
Hundreds of years ago there were severe penalties for injuring or killing a swan, and criminals could be jailed for a year even for stealing swan eggs.
Apart from the monarch there are only three organisations which are allowed to own swans - Abbotsbury Swannery since the 14th Century, the Vintners since the 15th Century and the Dyers also since the 15th Century.
They have maintained their unique marks for swans which are made on the birds' beaks, but those unmarked are owned by the King.
