The first Mersey road tunnel was constrcuted between 1925 and 1934, when it was opened by King George V. The consultant engineers were Mott, Hay and Anderson and the main contractor was Edmund Nuttall.
The tunnel is 3.24 kilometres (2.01 mi) long. It contains a single carriageway of four lanes, two in each direction. At the time of its opening it was the longest road tunnel in the world, a title it held for 14 years. The tunnel has two branches leading off the main tunnel to the dock areas on both sides of the river. The Birkenhead branch tunnel (known as the Rendel Street branch, or Dock Exit) was closed in 1965. The Liverpool branch tunnel remains in use, in the exit direction only. It emerges opposite the Liver Building, next to the Atlantic Tower Hotel.
The ventilation towers and entrances to the tunnel are Grade II listed. Of the 1,700 men who worked on the tunnel during the nine years of its construction, 17 were killed. Mersey Travel offer pre-booked tours of the tunnel which are strongly recommended.