The first tunnel under the River Mersey was for the Mersey Railway in 1886. The first tunnel crossing was proposed in 1825, and again in 1827. A report in 1830 rejected the road tunnel due to concerns about building damage.
During the 1920s there were concerns about the long queues of cars and lorries at the Mersey Ferry terminal so once Royal Assent to a Parliamentary Bill was received construction of the first Mersey Road Tunnel started in 1925, to a design by consulting engineer Sir Basil Mott. Mott supervised the construction in association with John Brodie, who, as City Engineer of Liverpool, had co-ordinated the feasibility studies made by consultant Engineers Mott, Hay and Anderson. The main contractor was Edmund Nuttall. In 1928 the two pilot tunnels met to within less than 25 millimetres (1.0 in).
The tunnel entrances, toll booths and ventilation building exteriors were designed by architect Herbert James Rowse, who is frequently but incorrectly credited with the whole civil engineering project. Their decoration is by Edmund Thompson. These are Grade II listed buildings. More than 1.2 million tons of rock, gravel, and clay were excavated; some of it used to build Otterspool Promenade. Of the 1,700 men who worked on the tunnel during the nine years of its construction, 17 were killed.
At the time of its opening it was the longest road tunnel in the world, a title it held for 14 years until the opening of the Vielha Tunnel in Catalonia, Spain in 1948, though it remained the longest underwater tunnel as of 1955. The tunnel, which cost a total of £8 million, was opened on 18 July 1934 by King George V; the opening ceremony was watched by 200,000 people.
By the 1960s, traffic volume had increased. In 1971 the Kingsway Tunnel opened to relieve congestion.