Manchester United will want assurances from Jose Mourinho that he understands the club's traditions and is willing to fall into line if they decide the former Chelsea manager should take over from Louis van Gaal.

While the club are giving serious consideration to moving out the Dutchman after three damaging defeats in a row, there is still concern at the highest level of Old Trafford about Mourinho's managerial style and specifically the elements of his work that led them to decide against employing him when Sir Alex Ferguson retired in 2013.

United are acutely aware of Mourinho’s strengths but also mindful about the amount of conflict he tends to generate as well as his reluctance to promote younger players.

Controversy

Ferguson regularly attracted controversy and had a fractious relationship with the Football Association but the feeling at Old Trafford is that Mourinho goes even further with his own outbursts and, in the worst moments, brought Chelsea into disrepute, leading to a one-match stadium ban this season.

If a job offer is forthcoming, it will be made clear to him that United expect a better standard of behaviour and historically place great importance on bringing through their own players.

United are deliberating about how long Van Gaal should be given after a sequence of three wins out of the last 13 games has caused the club to fall to fifth in the Premier League – a position that would mean Europa League football next season – nine points off the top.

Van Gaal’s position has been substantially weakened but, for now, he is trying to continue as normal. His weekly press conference has been pencilled in for tomorrow and Van Gaal even served the players their meal when they had their Christmas lunch at the training ground on Monday.

Noticeably, however, there has been no support for him behind the scenes, even in an off-the-record capacity, since it emerged he was genuinely in danger of the sack approaching the games at Stoke City on St Stephen’s Day and at home to Chelsea two days later.

United have been offered the chance to back, or defend, Van Gaal in the face of mounting speculation but have chosen not to say anything that would ease the pressure on their manager.

Mourinho has made it clear to United he wants the job, despite having a close relationship with the man he might ultimately replace, but sources in Portugal say it has not reached the stage where he has been made a firm offer. It is only two weeks since United let it be known they were so impressed with Van Gaal’s work they envisaged it might eventually lead to him remaining at the club after his current contract expires in 2017.

Elimination

What has followed since – a Champions League elimination in Wolfsburg and back-to-back defeats at Bournemouth and at home to Norwich City – has dramatically changed the picture, especially now Mourinho has become available and brings, in theory, a near-guarantee of silverware.

Yet it is clearly not a straightforward issue and has divided some of Old Trafford’s key personnel. Everything has changed very quickly given United’s executives had previously stated they were so impressed with Van Gaal they were even relaxed about the possibility of Manchester City hiring Pep Guardiola.

Mourinho, meanwhile, has been in contact with the Swansea City chairman, Huw Jenkins, over the last few days to offer a reference for Jose Morais, one of the candidates to take over as manager of the Welsh club. Morais was part of Mourinho's coaching staff at Internazionale, Real Madrid and Chelsea and one of the candidates Swansea had shortlisted, with Gus Poyet and Marcelo Bielsa, after Garry Monk's sacking. Guardian Service