I have a confession to make. I was a guest speaker at the Co-op Party summer school near Birmingham and I received £18 travel expenses.

Not quite the £50k that went to Ed Balls's office and was probably money better spent, but I defend the right of the Co-op to spend its money how it sees fit.

It is not as if private companies do not contribute money to political parties. And they do so out of sight with no democratic accountability.

The Co-op Union had a parliamentary committee as far back as 1881. The Co-op Party was formed in 1917 and has had an electoral arrangement with the Labour Party, the famous Cheltenham Agreement, since 1927.

It seems to have taken 66 years for this totally open activity to be finally "uncovered" by the right-wing press.

The Co-op Party is difficult to explain and many co-operators have been calling for reform.

With the rise of new Labour some felt it was too much about selling Labour to the Co-op and not enough about building an effective Co-op voice in Parliament.

Current events have remade the case for an effective Co-op political voice. It is worth remembering, as we approach the centenary of the first world war, why the Co-op Party was formed in the first place.

When the first world war began the co-operative movement did what it saw as its duty, with the Co-operative Wholesale Society (CWS) selling its stocks of flour to the army at pre-war prices, as well as selling Danish butter lower than the market price and granulated sugar and tea as well as canned goods at less than government prices.

Individual societies, in fairness to their members, introduced fair distribution schemes before the government introduced rationing.

When rationing was finally introduced it was run in the interests of private traders, with co-op societies not getting a fair allocation of controlled goods.

The CWS had built a powerful production and distribution chain which was far superior to any in private hands, yet was reduced to delivering the same poor-quality products.

This bias can be seen by Lloyd George's decision to appoint Lord Davenport - formerly Sir Hudson Kearley, a man who had made his fortune in the grocery wholesaling business of Kearley and Tonge - as the government food controller.

When conscription was introduced the movement found itself in the hands of its enemies, with military service tribunals often dominated by private traders.

One society had 102 out of 104 men conscripted. Across the country tribunals conscripted co-op branch managers to give a better living for the private grocer.

The final straw was the excess profits duty - a tax on Co-op Society surpluses. However these where not the profits of a private company but the mutual savings of the members.

As far as the movement was concerned this was a fundamental attack on the whole idea of co-operation. This tax would destroy the dividends of the members.

In 1916-17 the CWS alone paid over £1 million in excess profits duty.

Within the movement the argument raged about "political neutrality," one of the Rochdale principles - the set of ideals for the operation of co-operatives.

But as Arnold Bonner put it in his History of British Co-operation, "Political neutrality in these circumstances might bring the same fate as the pacifism of sheep among wolves."

At the 1917 Co-operative Congress in Swansea a resolution was passed which declared: "In view of the persistent attacks and misrepresentations made by the opponents of the co-operative movement in Parliament and on local administrative bodies, this congress is of the opinion that the time has arrived when co-operators should seek direct representation in Parliament."

Today the Co-operative Party has a structure a bit like its sister, the Labour Party.

It has individual members in branches and it has affiliated societies, the biggest of which is the Co-operative Group.

The irony of the present Tory attack on the Co-op-Labour link is that prior to this it was Ed Miliband's proposals for the trade unions affiliated to Labour that raised the biggest threat to the relationship between the Co-op Party and its affiliated co-operative societies.

The affiliated co-operative societies, as institutions, keep the party grounded in the real world of co-operative business.

And just as Professor Keith Ewing has so eloquently argued about the role of trade unions in the Labour Party, individualisation would break the institutional link between the party and the societies.

The present situation when that link is being attacked by the Tories and their mates in the media is hard to defend when Labour appears to have attacked it first.

However, what must be clear to everyone in the co-operative movement, the trade unions and the Labour Party is that ultimately we are all in this together. And as working-class institutions we have the right to determine our politics for ourselves.

A century of experience tells us that you simply cannot trust the Tories or the Liberals to act fairly.

Just like in 1917, "in view of the persistent attacks and misrepresentations made by the opponents of the co-operative movement," we need political action to be able to defend ourselves.

Nick Matthews is vice-chairman of Co-operatives UK. This column is written in a personal capacity