Chelsea Fume At Penalty Count  (Sky Sports)

Chelsea have stepped up their attacks on referees by claiming they have been awarded an "abnormally low" number of penalties in the Premier League this season.

The Blues have had just two penalties in 28 league games so far - compared to five spot kicks in just eight Champions League matches.

In an article on the club's official website, titled Penalty Puzzle, Chelsea compare the number awarded to them during the past six seasons.

The two penalties given to Jose Mourinho's men this campaign both came in home derbies - against Arsenal and QPR - and the club highlights that the most recent of those was four and a half months ago.

"Historically, this figure seems abnormally low," the club says.

The website lists the number of Premier League penalties given to Chelsea, season by season - seven in 2013/14, 11 in 2012/13, five in 2011/12, eight in 2010/11, and 12 in 2009/10.

The article continues: "So this season’s tally of two unquestionably bucks the recent trend yet our position as clear league leaders and second-highest scorers suggests we can’t be labelled anything other than an attacking side, spending plenty of time in the opposition box.

"Our two closest challengers in the Premier League this season, Manchester City and Arsenal, have both been awarded seven penalties – the most in the division. City have only scored one goal more than Chelsea and Arsenal two less.

"Last term, the two teams that finished above us in the league – Man City and Liverpool – were awarded more penalties than any other team bar us.

"Of course, it could be that when teams have played the league leaders they have been particularly careful inside their own area. We all have plenty of recollections suggesting this is not the case however.

"From the first half of our very first league game, at Burnley, a number of key penalty-box decisions have not gone our way, Diego Costa the victim that evening after being felled trying to round the keeper."

The website stokes the controversy following Mourinho's recent outbursts and comes after defender Branislav Ivanovic had a penalty claim refused in the weekend's 1-1 draw with Southampton.

Mourinho has been outspoken against referees all season, first suggesting in December that there was a "campaign" against his team.

That claim eventually led to a £25,000 fine and warning for the Blues boss from the FA, although it accepted his defence that he had been talking of a media campaign rather than one by referees.

But on Sky Sports' Goals on Sunday show last month, he went on the attack again, claiming referee Martin Atkinson had wrongly turned down two penalty appeals in Chelsea's match against Burnley the day before and had twice failed to issue the red card to Clarets striker Ashley Barnes.

He lambasted Barnes for the challenge on Nemanja Matic which led to the Serbia midfielder being sent off for his reaction.

He added that referees in general “are not doing well” as he called for the introduction of more technology to assist them.

And Mourinho claimed Chelsea had only one controversial decision in their favour this season, in contrast to all his perceived injustices against them.