Tom English: 'Until the end of the season Mowbray has a £45m team'

• Robbie Keane was all smiles when he arrived at Parkhead but will be more gloomy after last night's defeat to Kilmarnock

He doesn't seem to be doing too good a job at doing it himself. It's kind of fun anyway, isn't it? What with all the comings and goings at Parkhead, all the new faces and, er, same dreadful results. It's hard to resist really, this game of fantasy Celtic management. Even Rangers people would have been at it last night, between chortles of laughter.

These are days of penury in the SPL, but get this: until the end of the season Mowbray has a 45million team at his disposal. Near enough anyway. Oh sure, it's hardly an exact science calculating what each guy might be worth on the open market – especially now that belts seem to be tightening everywhere bar Manchester City – but whatever the precise number is, it ain't cheap, that's for sure.

Here's one way you could call it, although all of these numbers seem ludicrous in the wake of last night at Rugby Park. Artur Boruc stays in goal in the new Celtic and we'd rate him at about 4m. Heurelho Gomes went to Spurs for 7.8m and Craig Gordon went to Sunderland for 9m. Different days those, of course. We live in more straitened times now, but 4m is not a bad ball-park for Boruc.

Andreas Hinkel has upped his value since joining Celtic, so let's say 3m, and though it's hard to put a number on Edson Braafheid, who will surely now become the first choice left-back, he's regularly in the Dutch squad, so he's no mug. Call it 1.5m. Between them, Glenn Loovens and Joos Hooiveld come in at 4.5m. Well, that's what Celtic paid for them. Whether they're worth it or not is a moot point.

Up ahead, Landry Nguemo is a certain first-teamer and looks a 3m player most weeks. Beside him, Scott Brown, somewhere in the region of 6m if you believe the hype, which, I have to admit, I don't. Out wide, Aiden McGeady, let's call it 7m once he gets his finger out and starts playing again, and Diomansy Kamara, who drew a 6m fee out of Fulham only two-and-a-half years ago, but who we can knock down to 2m nowadays. In the attack, Robbie Keane – if he excels then he's probably going to return to somewhere close to the 12m valuation Spurs have put on him – and Marc-Antoine Fortune, who cost almost 4m. Again, there's a large question mark about that valuation, but let's go with it for now.

That's 45m, give or take. You might value McGeady higher and somebody else lower, but we're talking some high numbers no matter how you cut it. And we're not counting Georgios Samaras, Morten Rasmussen, Ki Sung Yeung or Shaun Maloney in that either. As for Thomas Rogne, Lee Naylor, Zheng Zhi, Mark Wilson, Marc Crosas, Niall McGinn, Paddy McCourt, Josh Thompson, Paul Slane, Paul Caddis and Darren O'Dea, let's just say that the Celtic reserve team is going to be pretty familiar from now on.

Mowbray managed to perform a very neat trick with Scott McDonald. The club's most reliable goalscorer was shipped out on Monday and yet the mood at the club come midnight was euphoric. For Keane was in the building. His capture should prove sound business, despite his failed beginning. His arrival lends desperately needed star quality to the SPL. We're either going to marvel at his ability or be gripped by his struggle, as was the case last night, in the coming weeks.

Keane's capture – as well as all the other members of the Celtic cavalry – present us with a fascinating final few months of the season. Don't doubt the fact that Rangers' fans are almost as galvanised by all of this business being done at Parkhead as Celtic people. They recognise a gauntlet being thrown down and appreciate straight away how sweet it would be if their club, on its uppers, were to defeat Mowbray's new creation. The gap remains at ten points, so nobody is going to be quaking at Ibrox just yet.

Denying Celtic the title this year would cause even more delirium at Rangers than when they took the best of what Craig Bellamy had to offer in his loan spell at Celtic – and he offered plenty – and yet still won the league. That's the precedent, argue the Rangers supporters. They defeated Bellamy, so they can defeat Keane.

Suddenly, the anticipation of what lies ahead has multiplied.

Mowbray has no excuses now for his team underperforming. The majority of the side is his and his alone. The Gordon Strachan pillars have been deconstructed and sent away in the back of a truck, bound for Middlesbrough.

So the horrendous loss at Kilmarnock is going to take some explaining. Dermot Desmond didn't lash out the readies for Keane in order to see him toiling against the Killies of this world, nor the Falkirks and the St Mirrens and the Hamiltons. If this continues much longer, then there is likely to be just one man Desmond will blame and that's Mowbray.

The test of his credentials as a Celtic manager have just moved to the kind of level where the air is rarefied – and he's gasping for his next breath. He has an expensive team with some star quality. But has he any idea what to do with it?

Liverpool were Keane's boyhood team, not Celtic

ONE other thing on Robbie Keane. If you look through the story of his life you will find constant references to his love of Liverpool as a boy. You will find quotes from Keane, from his family and friends and from the dogs on the streets of Tallaght where he was reared, telling of his devotion to Anfield. When he joined Liverpool in the summer of 2008 he made no secret of the fact that he was realising a dream. Wearing the red jersey, he said, was one of the more emotional things he'd ever done in football.

At his unveiling on Monday night, Keane spoke of his lifelong connection with Celtic, who in the flick of a switch had taken over from Liverpool as the club he loved most as a kid. If he was being honest, I would argue that what Keane would have said was that like most people in the Republic of Ireland, he had a soft spot for Celtic when growing up. He kept an eye on their results and such like. He followed Packie Bonner and the rest. But it was pictures of the Liverpool players he had on his bedroom wall and the English First Division he had in his mind when Saturday came.

We went through this myth with Roy Keane as well; a childhood Spurs supporter recast in the media as a lifelong Celtic fan the minute he walked into Parkhead. Robbie went with the flow on Monday and good luck to him. No doubt he was moved by the extraordinary reception the fans gave him. Infinitely better than the welcome he received at his dream club Liverpool, for sure.