You have to go back to 1938, when Manchester City were relegated after winning the First Division championship the season before, to find such a terrible turnaround in fortunes.

Some pundits are trying to claim they saw it coming towards the end of last season, arguing that Chelsea did not finish off the campaign as strongly as they started.

That does not bear scrutiny, as Chelsea’s last 16 games yielded 35 points - if they had played to that level in the current campaign they would be level on points with leaders Leicester (albeit behind on goal difference) and two or three ahead of Arsenal and Manchester City.

And Chelsea were probably slightly better than that on the run-in, as their penultimate result of the season was a 3-0 defeat at West Brom after the championship had been secured - Mourinho’s title-winning teams usually throw in a poor result like that once the pressure is off.

With the same manager and pretty much the same playing staff, Chelsea should have been competitive in the upper reaches of the table again this season, even if it is possible to argue (as Mourinho will probably do in the weeks to come) that their lack of summer spending left them vulnerable to rivals improving past them.

Undoubtedly some cracks were evident - the ageing legs of John Terry and Branislav Ivanovic in defence, the lack of cover if Diego Costa’s goals dried up - but nobody seriously expected those weaknesses to widen into gaping holes in Chelsea’s defence of the title.

The biggest problem appears to have been a growing disconnect between Mourinho and his players - or “palable discord” as Chelsea’s sporting director Michael Emenalo termed it on Thursday.

From the moment Mourinho rounded on his medical staff on the opening day of the season, the ructions inside the club have been a talking point and they reached a head when the manager accused his players of “betrayal” in Monday’s 2-1 defeat at Leicester.

In terms of form, Chelsea have not had an up-and-down season in the Premier League as you might expect of an under-performing team with residual class. Their results have been pretty much uniformly what you would associate with a struggling side - they have been bad against teams from the top half of the table (their record of W1 D1 L6 is the same as Sunderland’s in that respect) and have picked up most of their points against fellow strugglers (11 points from six games against bottom-eight teams, similar to the hauls of Swansea and Norwich).

And yet Chelsea topped their Champions League group with a record of W4 D1 L1. It was not the strongest group, but it is still interesting to note that they were able to reach the knockout stage of the elite club competition with some comfort (conceding only three goals in six games) whereas their Premier League rivals went for the kill once they scented blood (Chelsea’s 26 goals-against in 16 games ranks them as the sixth-worst defence).

Perhaps that is another sign of the overall strength of the Premier League, as discussed in this column last week. Once the weakness of Mourinho’s team became apparent, their better-class opponents allowed them no hiding place.

It would be an almighty shock if Chelsea went down, but it is going to take a long time for faith to be restored (the rule of thumb for punters is to wait for three good results in a row).

Instead, faith in strong form now rests with Leicester and they rate well on the handicap again for their visit to Everton.

The other away teams to consider are Tottenham, Crystal Palace and Bournemouth, while Arsenal are the handicap pick for Monday night’s big clash at home to Manchester City.

The Gunners have the best record in the mini-league of the top eight teams, whereas City’s form has become questionable since their five-win blitz at the start of the season.