PETER Lawwell, the Celtic chief executive, was last night warned he will face a furious backlash from irate supporters this summer if the Parkhead club fails to invest heavily in new players.

And Lawwell has been urged to appoint Neil Lennon, who has taken over from Brendan Rodgers as manager until the end of the season, on a permanent basis immediately to enable him to start building for next season now.

Mark Wilson, the former Celtic right back who now works as a Radio Clyde pundit, is confident his former club will win their eighth consecutive Scottish title in the coming weeks despite the surprise departure of Rodgers for Leicester City.

But several of the double treble winners’ players are set to depart at the end of the 2018/19 campaign when their contracts expire or their loan deals run out – including Filip Benkovic, Dedryck Boyata, Oliver Burke, Emilio Izaguirre, Mikael Lustig, Jeremy Toljan and Timothy Weah.

And Wilson feels it will be a “catastrophic” if the Glasgow club fail to triumph in the league next term and reckons fans who are furious at the sudden exit of their manager before the end of the season will turn their anger at the chief executive instead.

Rodgers was, despite bringing in Odsonne Edouard for a club record £9 million fee from Paris Saint-Germain, deeply unhappy at the transfer business Celtic conduced last summer and was particularly frustrated with their failure to land John McGinn from Hibernian.

Wilson, who won every honour in the Scottish game during his six years at Parkhead, believes Lawwell will incur the wrath of the Celtic fans if they are unable to land their targets in the close season for a second year running.

“I definitely think there’s a lot of work needed,” he said. “Even if there wasn’t a lot of players out of contract, it would still be a tough job for whoever is in charge next season for the next manager to replicate the success. Celtic have to lose a trophy at some point. You can’t keep winning everything.

“The fact the new man, whether it’s Lennon or anyone else, will need to change so many players makes it an even tougher job. Not just for Lenny either, but for Peter Lawwell.

“If Celtic go on to win this eighth title – which is looking likely – then you are talking about the nine-in-a-row year. Peter and the club will need to throw a good bit of money at this because Celtic can’t afford to fail.

Rangers have put up a decent challenge this year and you’d think they will be stronger again next seasons. It would be catastrophic if they didn’t do nine and the fans would never forgive the board if they didn’t splash the money.

“The fans were going off their nuts because they felt the club didn’t invest to get to the Champions League. Can you imagine the response in the summer? It would be 10 times worse if they didn’t spend money on replacements.

“There will be criticism labelled at him (Lawwell). With Brendan leaving now, I don’t think people are pointing the finger at Peter. That was Brendan’s decision made for his own reasons rather than the club’s.

“But the fans will look back to the summer when there was a fallout between them. The John McGinn thing keeps popping up and how it stuck in Brendan’s throat. If there’s something similar in the summer then there’s only one guy who was there for two or three windows and that’s Peter.

“The finger will be pointed. When you look at the numbers going out the door there has to be a need for quality replacements, not guys for £300,000. It needs to be quality.”

Wilson, who played alongside Lennon and under him at Celtic, feels it makes sense to appoint his old team mate and manager now given his experience in the role and the massive rebuilding job that needs to be overseen.

“I don’t see why not,” he said. “He ticks all the boxes and if you give him the job now it gives him time to start thinking about it.I know he’s got a tough job right now with the semi-finals and the league. But Neil, like all top managers, will want to prepare for next season.

“He’s got a great track record with John Park (former football development manager) before. I don’t know if that’s an option if Lee Congerton (current head of recruitment) moves on, but they worked incredibly hard to bring in good players.

“Don’t get me wrong, there was some s**** in there as well! But he mainly brought in crackers.

“He will want the opportunity to get to work but Peter will be watching this very closely. If he doesn’t win the league by the same points gap or win the cup, then it might be a problem.”