Coach operator FlixBus has announced the return of the 666 bus service to the Polish seaside resort of Hel.

It resurrects the controversial so-called "Highway to Hel" bus journey formerly run by local company PKS Gdynia.

Religious conservative groups fiercely opposed the "satanic" association of 666 with Hel, so in 2023 the number was changed to 669.

The new 13-hour route run by FlixBus will connect Kraków to Hel, passing through other major Polish regional towns and cities including the capital Warsaw.

FlixBus spokesperson Aleksander Kalenik told the Polish news service TVN24: "The number 666 was deliberately chosen as a marketing communication element, intended to increase the visibility of the connection on the popular holiday route to Hel."

Back in June 2023 a PKS Gdynia spokesperson had told media: "The management board buckled under the weight of letters and requests that were sent to us, maybe not in large numbers, but periodically for many years with a request to change the line number."

One Polish religious group had accused the bus company of "spreading satanism".

The Bible identifies 666 as the "number of the beast" and Hel is just one "l" short of the English word "hell".

Poland is a predominantly Roman Catholic nation, where the Church has traditionally been influential.

Hel is located on the tip of the 22-mile (35km) Hel Peninsula, which juts off the northern coast of Poland in the Gulf of Gdańsk.

Tourists have been drawn to Hel's sandy beaches, ancient architecture and seal sanctuary.