Dylan Hartley has rounded on the former Northampton players who have voiced their criticism of the club after a woeful run of form that cost Jim Mallinder his job as director of rugby last week. On another difficult day for the struggling Saints, Wales also brushed off the club’s attempts to lure Warren Gatland to Franklin’s Gardens.

Mallinder was sacked on 12 December after a decade at the club but on Sunday Northampton’s losing run in the Premiership and Champions Cup extended to nine matches. Recent results – and the steady decline since winning the Premiership in 2014 – have led to several former players voicing opinions over where Saints have gone wrong, with the former England wing Ian Hunter pointing the finger at the forwards coach, Dorian West, last week.

Asked about comments made by former Northampton players on social media, Hartley said: “I’d tread lightly on that sort of stuff and unless you were sat in our changing room, in our kit, I don’t think you should take any opinion or advice from people who are not in our group.

“It’s not fair unless they know and if you’re not sat in our changing room you don’t know. And at a time like this, when you haven’t had a win, it’s easy for people to point fingers, especially if you’re not involved.”

Hartley did acknowledge that the current Northampton squad, who face the champions, Exeter, on Saturday must take responsibility for their plight, as well as for Mallinder’s. “There’s nowhere else to look other than ourselves for improvement and results now. The spotlight is on us. We’ve been through periods like this before and it is rough but we’ll come out the other side of it. Four seasons ago we were at this stage at Christmas time and then as the close of the season came we had to win every game to make the top four. We ended up doing it, so it’s do-able, there is a way out.”

Wales, meanwhile, have told Northampton to forget about attempting to bring Gatland to the club. The president, Keith Barwell, said this week that they had shortlisted Gatland before appointing Mallinder 10 years ago and that the Wales head coach, who also led the British & Irish Lions on their past two tours, was someone in whom the Saints are interested.

“I did not lose a beat to be honest,” the Welsh Rugby Union chief executive, Martyn Phillips, said when asked for his reaction to Barwell’s remarks. “Warren is going to get linked to all sorts of jobs because he is one of the top coaches in the world. There are so few people on that list that those who are will be talked about a lot. I would like to believe he will be here for the World Cup [in 2019].”

Gatland’s contract with Wales lasts until the end of that tournament and a three-man shortlist has been drawn up for his successor. It would cost Northampton a seven‑figure sum to buy Gatland out of it because as well as his salary, he will receive a bonus if he sees out his time in the country he moved to 10 years ago.

Whoever takes over from him – Glasgow’s head coach, Dave Rennie, is the favourite – will be expected to work closely with the country’s four regions. Phillips said that the professional end of the game was now made up of five interdependent bodies, Wales and the quartet, a contrast to the previous WRU regime which erected a barrier between the national side and those under it.

“It is important that the successful candidate sees the big picture,” Phillips said. “We want a pretty rounded individual, not just a great coach, although it is important that he has a track record and has won something important, and nationality is not an issue. We have a shortlist of three and they all have to buy into our model: it is not random any more.”

Phillips also said the WRU is considering making a part of the Principality Stadium an alcohol-free zone after the next Six Nations following complaints from spectators last month about fans constantly getting up during the match to go to the bar or the toilet. “We are collecting data from spectators and if there are things we think we can do to improve the experience for people, we’ll trial those next autumn, but I don’t want to penalise one group against another,” he said.