Inside secret underground tunnels you’d never know run under Birmingham city centre

The eerie 400m-long tunnel was used by Royal Mail workers to transport mail between a sorting office and New Street Station and was built in 1970

These mesmerising photos unveil the secret postal railway system that functioned beneath Birmingham’s streets for many years.

The spooky 400m-long tunnel was utilised by Royal Mail employees to shift deliveries between a sorting office and New Street Station.

Constructed in 1970, it allowed electric trucks to haul cages brimming with letters and parcels from trains, before transporting them to the office for sorting.

See inside in the gallery below

READ MORE: Inside the tunnels running under The Mailbox in Birmingham

The office, now known as The Mailbox, was the largest of its kind in Britain.

The post was then loaded onto what were referred to as ‘electric tractors’, which conveyed the mail along the tunnel to the train station.

For decades, this rail mail system circulated post around the city, but it ceased operations in 1998 when the sorting office relocated to Aston.

The tunnel, absent from any maps, has been made accessible to the public for the first time through a series of limited guided tours.

A draw for the inaugural guided tour attracted 1,500 applicants for a mere 30 spots.