Parker joined United from QPR in the summer of 1991 and went on to win two Premier League titles as well as the 1994 FA Cup alongside the likes of Keane, Steve Bruce and Eric Cantona.

The 56-year-old ex-England international feels the current group lack the "identities" needed to call each other out when times get tough.

"You look at those results and the players have lost their way now, you can see it," Parker told the PA news agency.

"You cannot forgive them for that, because you are looking for them to add that little bit of self-motivation and pride.

"That bit of pride to say: 'we are not going to go on and concede that many'.

"There should have been a lot more fight – football has changed, there was a lot more self-motivated players in my time than there is now.

"United are missing players with identities, who have come into the club from places where they have had to dig deep and they have come in looking to achieve and win things.

"When you look at someone like Bruno Fernandes, he wants to prove a point – he has come from a massive club, a very famous club in Portugal, and has come to United looking to prove himself again, and you cannot knock that.

"But maybe some of the players they are getting in, a few of them are content, happy to be there, and think that it is an easy ride.

"That is the big difference – when I joined United a few players were keeping an eye on me to see what I was going to do. Was I just content to be there or did I want to join them and help them, to make their life easier in winning trophies?

"At this moment in time, I am looking at Manchester United, and they have become a 'buy buy' club. However, a lot of the work has to be done on the training field, but with the right people.

"You have to voice an opinion at individuals – are you going to accept if you have made a mistake and not taken responsibility that I am going to point my finger in your face? I am going to turn around and tell the home truth, maybe at half-time or after a game.

"How are you going to deal with that? Are you going to try to prove me wrong or are you going to sulk, blank me and go to talk to your agent?

"Or are you going to have the character to accept what you have or have not done, then go out and prove me wrong in the second half or in the next game?

"Building a team by how much individuals cost doesn't always guarantee anything, because it is just about finding players who talk to each other."

Parker, who left United to sign for Derby in 1996, believes the continued absence of supporters in the stands is also having an impact on players' performances.

"People in the stadium make a difference, certain players need adulation, they need their ego massaged," said Parker, who is supporting Prostate Cancer UK's online risk checker campaign.

"The games are deteriorating because the players are struggling, they are getting no adulation now.

"Some of them are doing unbelievable stuff, but they have no celebration (with the fans).

"They have not got anyone singing their name during the game, or when they run out for a warm-up. They are getting nothing back at the moment."

:: Prostate cancer is now the most commonly diagnosed cancer in the UK. To help men understand their risk, Prostate Cancer UK has launched an online risk checker at prostatecanceruk.org/riskcheck