As Middlesbrough's Labour group leader was toppled yesterday, the battle to elect a mayor is becoming increasingly like a game of chess. Political Editor Chris Lloyd examines the moves.

THE battle to be king in Middlesbrough has become a grand game of chess. Spectators, both regional and national, have been drawn to the drama as the players move their pieces in increasingly complex ways as they look for a winning strategy.

Yesterday, Ken Walker found himself in checkmate, captured, extraordinarily, by his own side.

The man who has led the local Labour group for seven years - and who was leader of the council and chair of the police authority - was ousted by one vote.

It was a move Mr Walker himself had not seen coming, although it can be traced back to his decision last summer to ask the people of Middlesbrough if they wanted a new, directly-elected mayor. That decision, taken to bolster his own position, has created the possibility that Labour may lose power in the town to Ray Mallon in a fortnight's time. At Monday night's annual general meeting, that possibility proved too much for his own party and his fellow councillors decided to grab the board and re-position the pieces in the hope that some power might still be salvaged.

And caught up in this fascinating powergame are the local MP and the local Chief Constable as well as Robocop himself.

The Middlesbrough Labour Party needed some convincing last year that calling a referendum on a new mayor was a shrewd move. But Tony Blair was backing the position which he hoped would reinvigorate local democracy. And Mr Walker is a Blairite, as Middlesbrough's pioneering - if controversial - use of public/private partnerships has shown.

But prior to the election in October, Mr Mallon had made his move, letting it be known that if there was a "yes" vote, he would be among the candidates.

There was a "yes" vote, a resounding one. Eighty-four per cent were in favour - the biggest, by a large margin, in the whole country. As Middlesbrough MP Stuart Bell said, it was down to "the Mallon factor".

As the election neared, Operation Lancet dragged on, and Mr Walker found himself chairing meetings which would decide whether Mr Mallon could be freed by the police to stand against Labour.

Now Mr Walker conceded, at least in private, that he was too "damaged goods" to present himself as the Labour candidate and so his deputy, Sylvia Connolly, reluctantly allowed her name to go forward.

The fatal blow to Mr Walker came in February, when Mr Mallon, having protested his innocence for more than four years, suddenly pleaded guilty and extricated himself from the police. He was now going head to head against Mr Walker's Labour group.

The campaign began in earnest a fortnight ago, with The Northern Echo's poll suggesting that Mr Mallon had 40 per cent of the vote, Mrs Connolly nine per cent and a potentially decisive 43 per cent were undecided.

Labour has insisted throughout the campaign that its polling shows its vote holding up. Yet yesterday, Mr Walker, the architect of the ballot, walked the plank.

The reason for the mutiny could just be that the local Labour Party is a notoriously unstable ship. A breakaway group from the 42 Labour councillors did make overtures to Mr Mallon about him becoming the party's candidate and, once he had decided to stand as an independent, a handful began actively campaigning for him.

Mr Walker's leadership has also rarely been plain sailing. He won the post seven years ago by a single vote, and faced a serious challenge three years ago from Councillor Barry Coppinger. He won then by 24 votes to 17, partly because Mr Coppinger was considered too much of a maverick left-winger. This time around, Mr Walker's challenger Councillor Paul Thompson is considered more of a pragmatist than a traditionalist and so, by 21 votes to 20, was acceptable.

It could even be argued that, despite Mrs Connolly supporting Mr Walker, her position is strengthened by his departure. Now there are no goods damaged by Lancet behind her and the new leader, Coun Thompson, has actively backed her campaign.

However, other Labour sources suggested the words "sinking ships and rats" sprung to mind.

Although Mr Walker insisted yesterday that he "was not an enemy of Ray Mallon", he did in February question whether the former policeman was a "proper and decent person to hold such high office". Mr Mallon holds a similar opinion of Mr Walker, and should Mr Mallon have won the election, it was hard to see the two working together in perfect harmony. Middlesbrough could have been gridlocked, as mayor battled with the leader of the largest political group.

But yesterday, sensibly, Mr Thompson was burying hatchets. "It is an olive branch to whoever the elected mayor is," he said of his election. "I'm hoping that's Sylvia Connolly. One way or another, Middlesbrough will have a brand new concept in politics that no one has really explored before. I think it is conciliatory politics. People have to make accommodations."

Among Mallonistas, there was speculation yesterday that the new Labour leader could be offered a place within Mr Mallon's cabinet, possibly even deputy leader, should Mr Mallon win.

While the election campaign, and the operation of the new mayor's office, will remain the main focus of attention, there are other side issues that spring from yesterday's toppling of Mr Walker.

There is the position of Mr Bell to consider. Over Lancet, he has allied himself very closely with Mr Walker, not least with his extraordinary use of Parliamentary privilege to accuse Mr Mallon of lying and defrauding local taxpayers of £700,000. In return, Mr Mallon has been trying to label Mr Bell "the absent MP" - a feud that is sure to continue should Mr Mallon be elected.

Despite Mr Bell's overwhelming majority in elections, he is not universally popular within the local party - The Northern Echo has been aware for years of a whispering campaign against him.

Now Mr Walker has gone, he will have to ensure the whisperers don't get the ear of the new leadership.

And then there's the position of the Cleveland Chief Constable, Barry Shaw. He could have retired five years ago but, commendably, has remained at his post under heavy fire, while others around him have deserted. He said in yesterday's Evening Gazette that he could continue even if Mr Mallon wins the election because "as mayor, Ray Mallon would have nothing to do with policing".

Yet Mr Shaw has called Mr Mallon "a proven liar" and said he was at the centre of an "empire of evil". Should Mr Mallon win, law and order will be one of his priorities. The two will have to work in partnership.

And with Mr Walker gone, Mr Shaw has also lost a key ally. So far, Middlesbrough is the only one of the four Cleveland councils not to have adopted a line questioning the force's budget and, implicitly, Lancet.

Mr Shaw will hope that Mr Walker, despite having lost his leadership of the Labour group, manages to cling to his chair of the police authority.

In such political games of chess, the people are often the pawns. But on May 2, they will have the final say over who will be king and who will be the next casualties in this enthralling drama.