Not if he gets back for another full term. 10 years without a majority. Lucky bugger. That's politics. John Major was seen as a failure, yet he was 6+ years PM and got the largest vote ever in 1992 with 14 million votes. More than Thatcher, more than Atlee, more than Blair, more than Churchill.
Think it would be much fairer to compare largest vote on percentage terms (since the war for ease) given the massive fluctuations in turnout and population:
Eden 1955 - 49.8%
MacMillan 1959 - 49.6%
Wilson 1966 48.0%
Churchill 1951 - 48.0%
Attlee 1945 - 47.7%
Heath 1970 46.4%
Attllee 1950 - 46.1%
Wilson 1964 44.1%
Thatcher 1979 43.9%
Blair 1997 43.2%
Thatcher 1983 42.4%
Thatcher 1987 42.2%
Major 1992 41.9%
Blair 2001 40.7%
Wilson Oct 1974 39.2%
Heath Feb 1974 - 37.9% (or Wilson Feb 1974 37.2% if we're only including PMs)
Cameron 2010 36.1%
Blair 2005 35.2%
The trend is pretty clear, our electoral choices have massively diversified with 1974, 1983, 1987, 2005 and 2010 elections being clear indicators of this. For a government in our country to have any legitimacy at all we need a reform in voting system otherwise were stuck in this situation where more than 50% of the country can vote for a left-leaning party but the Tories get in (1987, 1983). Problem is with the electoral system being designed in a way that the two parties who would never push through that reform, or be interested in convincing people of why that reform is necessary, are going to eternally govern us. My personal suggestion would be for all parties that support voting reform to start hammering the benefits to people now and stand unity candidates in 2020.