If Esther McVey loses her seat of Wirral West on 7 May, the Conservatives will have been wiped out across the whole of Merseyside.

It would be the final act in a drama that has unfolded slowly but steadily over half a century, and will represent a remarkable turnaround in fortunes for a party that was once the most popular political force in this part of England.

The city of Liverpool is the crucible from which the decline of the Tories spread. It currently comprises five constituencies: Garston & Halewood, Riverside, Walton, Wavertree and West Derby. Both Walton and West Derby have existed since 1885. But the last time either seat boasted a Tory MP was in 1964.

The Tories held Walton continuously up to 1964, except for a Labour MP between 1945 and 1950. Labour has held it continuously ever since. Conservative majorities in Walton were never that great, and by the middle of the 20th century it had become a seat contested only by Tories and Labour. In 1959 – the last Tory victory – Kenneth Thompson managed a majority of 4,034. The turnout in Walton in that election was 77.7%; in 2010 it was 57.7%.

In West Derby there was also a Tory MP as late as 1964. But this seat stayed blue even in the Labour landslide of 1945, though a Liberal candidate held the seat between 1923-24. Labour held it from 1964 to 1981, when the sitting MP Eric Ogden defected to the SDP. He lost in 1983 to Labour’s Bob Wareing, who became an independent MP in 2007 in protest at being deselected by his local party in favour of Stephen Twigg, who went on to win the seat in 2010.

The other three current Liverpool constituencies, Garston & Halewood, Riverside and Wavertree, have never had a Tory MP, although in its previous guise, Wavertree had a Tory MP until 1983. This was when the constituency had different boundaries to today, and didn’t include so much inner city areas or housing estates. The last election for this seat took place in 1979, in which Tory MP Anthony Sheen won a majority of 6,942. In total the Tories held this version of Wavertree from 1918 to 1983, barring a year of Liberals in 1923-24 and a few months of Labour in 1935.

Now let’s go back through history to look briefly at the other incarnations of Liverpool seats.

Broadgreen and Mossley Hill existed between 1983 and 1997. The former was held by Labour; the latter by the Liberals, then the Liberal Democrats.

Garston existed from 1950 to 2010. The Tories held it from 1950 to 1974, when Labour won the seat. The Tories took it back in 1979, only to lose it again in 1983 to Labour, who held it until 2010.

Toxteth existed from 1950 to 1983. From 1950 to 1964 it was a Conservative seat, then Richard Crawshaw won for Labour, who retained the seat until its abolition, although he defected to the SDP in 1981.

Edge Hill existed from 1918 to 1983. Labour won the seat from the Tories in 1945, but lost it to the Liberals in 1979.

Fairfield was created in 1918 and abolished in 1950. It was held by the Tories for its entire existence bar the five years from 1945-50, when it was held by Labour.

This leaves the seven constituencies that, along with Walton and West Derby, were created back in 1885:

• Abercromby, 1885-1918: Conservative, except 1906-10 (Liberal)
• East Toxteth, 1885-1950: Conservative, except 1906-10 (Liberal)
• Everton, 1885-1950: Conservative, except 1929-31 and 1935-50 (Labour)
• West Toxteth, 1885-1950: Conservative, except 1924-31 and 1935-50 (Labour)
• Exchange, 1885-Feb 1974: Conservative for one year, then Liberal from 1886 to 1910, then Conservative until 1945, then Labour
• Scotland, 1885-Feb 1974: Irish Nationalist until 1939*, then Labour
• Kirkdale 1885-1983: Conservative to 1929, Labour to 1931, Conservative to 1945, Labour to 1955, Conservative to 1964, then Labour (although its MP defected to the SDP in 1981)

In summary, the last time a Tory MP represented any part of Liverpool was in 1983 (in Garston and the former constituency of Wavertree).

Going into the 1964 election, the Tories had six seats in Liverpool: Walton, West Derby, Wavertree, Garston, Toxteth, Kirkdale. After the 1964 election, they had just two: Wavertree and Garston. It was pivotal year in the fortunes of the Tories on Merseyside. After 1964 the party went into decline and never recovered. It’s interesting to speculate on why this happened. Possible reasons could be the changing nature and outlook of the population of Liverpool (less deferential, more working class), the political profile of the Conservatives (less centrist, more right-wing), the dilution of traditional religious loyalties and affiliations, and the growth of the Liberals (and Liberal Democrats) as a third party.

Since 1983 Tory MPs have continued to exist in Merseyside, but only outside of Liverpool. These have slowly disappeared, however. Wallasey went to Labour in 1992; Wirral South fell to Labour on an almighty swing of 17.2% at a by-election in 1997; and Southport was gained by the Lib Dems in the same year.

For the past 32 years there have been no Conservative MPs in Liverpool. 2015 could represent the first year in which there are no Conservative MPs in the whole of Merseyside.

*Liverpool Scotland was the only constituency outside Ireland ever to return an Irish Nationalist Party MP: TP O’Connor.