The email trail that leads to Excalibur

The trail of emails that led from Stephen Byers' private office at the Department of Transport to the Labour Party's Millbank headquarters could blunt its prized election weapon, Excalibur – the computer database on which it relies for "fast rebuttals".

The disclosure that Mr Byers' special adviser Dan Corry had asked for party workers to run a check on the Paddington rail crash survivors campaign group yesterday led to calls for the party's data files to be opened up for inspection. It threatens to turn the Corry emails into an even more embarrassing problem for Labour.

When The Independent broke the story last week that Mr Corry had asked for information on the Paddington group, the new Secretary of State for Transport, Alistair Darling ordered a search to be made, and for the results to be put out into the open.

His aides turned up nothing. It was only on the second day of the disclosures that they realised that the emails had been sent to the Labour Party headquarters. They then did a second search and uncovered the exchanges published between Mr Corry and Millbank. They included:

Corry: Can you get some sort of check done on the people who are making a big fuss on the Paddington Survivors group?

Millbank: What sort of check?

Corry: Basically, are they Tories?

An unnamed Labour party worker did the checks using Excalibur but found no references to them being members of the Tory Party. Mr Corry said Martin Minns worked for a PR company and asked for more information. Excalibur failed to find any more on him.

The email trail rang alarm bells across Whitehall because it demonstrated once again that emails could become political dynamite if they are uncovered. Elizabeth France, the commissioner for information, yesterday detonated the charge by reminding people they have a right to see their computer files.

Already, Mr Minns is demanding to see any references to him on the Labour Party computer and more are likely to follow.

Meanwhile, Mr Darling is demanding his staff go through the systems to find any more potentially embarrassing emails in the Corry chain that were sent before his arrival. His spokesman said they intended to send out a signal that things had changed by promising to go public with any more emails, if they were discovered.

The whole episode has given the impression of a government paranoid about criticism, in spite of its massive Commons majority. Excalibur may be part of the problem, feeding the "Opposition" mentality of a party constantly under attack, rather than a confident government.

In 1999, Labour ran advertisements for a "new head of attack" to run Excalibur. The language of attack was seen as further evidence of a party that still felt insecure.

Excalibur was honed in the days when Labour was fighting to establish its credibility as a party in opposition after the disappointments of the Kinnock years. It was intended to give party workers the kind of fast response that had proved invaluable in America in winning the presidential election by Bill Clinton's apparatchiks.

In Britain, it was used with powerful effect to kill negative stories by Tory-supporting newspapers in the run-up to the 1997 election by Labour's rebuttal squad before allegations had done any damage. Armed with fast access to key facts, from past quotes by Tory ministers to figures for constituency unemployment rates, Labour party workers could challenge any assertions by their opponents within minutes.

The data bank was built up by the new breed of young, computer-literate party workers who were keen to keep Labour ahead of the technology game. Chief among them was Frank Dobson's special adviser, Joe McCrea, now in No 10. He was capable of giving the then Health Secretary damaging details about opponents' policy positions while Mr Dobson was on his feet speaking.

The Labour party is keen to play down the significance and abilities of Excalibur, as well as any suggestion that it was used as an electronic black book of "dirt" on political opponents.

Eddie Morgan, the party's new assistant general secretary, insisted yesterday that the computer system was actually just a "search engine" and that all information contained on it was "drawn from the public domain".

Mr Morgan said there was a "mythology" about the system and a journalistic "obsession" about Excalibur. "If you were to use your brains you would realise that we don't have this information because we couldn't give any information to a political appointee [Dan Corry]," he said.

"The Labour Party doesn't hold sensitive or inappropriate information on individuals in the first place."

Uh-oh, you've got mail: electronic memos that caused a stir

Dan Corry and the Paddington survivors

A special adviser to the former Transport Secretary Stephen Byers, Corry asked Labour HQ to dig up information on Paddington survivors on 23 May 2002. The email read: "Can you have some sort of check done on the people who are making a big fuss on the Paddington Survivors' Group attacking SB please."

Jo Moore and the 11 September news fix.

As millions watched the World Trade Centre collapse on 11 September, Moore, a favoured press aide of then Transport Secretary Stephen Byers, wrote: "It is now a very good day to get out anything we want to bury. Councillors expenses?" Despite a televised apology she was later forced to resign.

Martin Sixsmith and the "buried" bad news

Sixsmith, then head of communications at the Department of Transport, sent his boss Stephen Byers an email protesting about plans to issue bad news on the day of Princess Margaret's funeral on 14 February 2002.

It allegedly led to his dismissal.

The Poet Laureate and the romantic messages

Andrew Motion, the Poet Laureate, was cleared last year of sexually harassing a female student at the University of East Anglia, after sending her more than 40 "intimate" emails. But university officials said that his conduct was "unwise and inappropriate."

The journalist and the minister

Using freedom-of-information rules, the comedian and TV presenter Mark Thomas uncovered a series of abusive emails about him written by officials in the Department of Trade and Industry. One email, from 3 May 2000, claimed the trade minister Richard Caborn wanted "dirt" to be dug on Thomas.