It was a pathetic shadow of a man who the Sunday World found last weekend outside the rundown Donegal cottage he now calls home. Nobody expected him to have been leading the high life since his unveiling as a British spy. But this was a shock.

The top Shinner, once entertained in the White House, living in a pre-famine hovel with no electricity or running water.

Unshaven, thin and raggedly dressed, here was a man whose world had collapsed.

Journalist Hugh Jordan offered to take him for lunch or a pint. Donaldson declined.

How many pubs or restaurants would want his custom? Most people would wish him no physical harm but few would look him in the eye without derision.

The informer, even by those implacably opposed to paramilitary violence and the whole idea of 'armed struggle', is still regarded as low-life in Irish society. The feelings of republican grassroots are understandable but, technically, Donaldson should be feted in some quarters.

For over two decades, he loyally served the crown. Yet, ask any senior police officer, British army officer or British government official in the North if they admire him, and there'd be silence.

Donaldson should be a hero to unionists.

He was the hidden enemy within their greatest enemy. His contribution to the IRA's defeat was worth a thousand rants from the Rev Ian Paisley. Yet had Donaldson arrived at the DUP's annual conference last month, he'd have been chased off.

An idealistic view of informers has them as brave, noble individuals. But those senior figures who turn informer are usually driven by one factor alone . . . money. It isn't always their original reason for informing, but it's what keeps them at it. How many have ever given their services free?

It's not just covering expenses: big bucks are made at the top of the spying game.

Few inform for ideological reasons. A paramilitary with a genuine change of heart could simply leave the organisation.

If they felt they wanted to do something to save lives, they'd ring the police confidential telephone line and relay what they knew. Then, they'd walk away.

Being an informer is poisonous. We all lie about something to somebody at some stage of our lives . . . to our partners, friends, bosses, or neighbours. But an informer lies to everybody about everything, 24/7.

Their entire life is a lie. What child grows up dreaming of becoming an informer?

Low-level informers are often vulnerable people who are either struggling financially or are being blackmailed by Special Branch. Caroline Moreland, 34, shot dead by the IRA in 1994, had been allegedly passing on information for £50 and £100 a week. Donaldson was in a different league to a naive west-Belfast single-mother-ofthree. There's a rumour he was recruited after being caught shoplifting from Marks & Spencer. Even if that's true, he was too smart and wily to allow himself to be coerced into spying for 20 years over a minor offence.

And he wasn't a troubled soul. He enjoyed the women, the craic, and the access to the corridors of power his role in Sinn Fein gave him. He could look at the photo of himself, with his arm around Bobby Sands, and not flinch. Maybe it was a game he got kicks out of: 'See how clever I am, the spider in the web, controlling them all!'

Informers undoubtedly save lives. Plenty have taken life too. Ex-IRA internal security head Freddie Scappaticci joked about murders. Portadown IRA man Gregory Burns gave information which led to his own brother's death in an RUC shoot-to-kill operation in 1982. Even after that, he continued spying, and later killed his girlfriend, Margaret Perry, for knowing too much.

When questioned by the Sunday World, Donaldson stuck to the nonsensical Sinn Fein line that there was no spy ring at Stormont. Clearly, he's done a deal with the Provos: staying alive in exchange for parroting propaganda. But where are the hundreds of thousands of pounds the Brits paid him over the years? He can't have spent it all, and it seems strange he'd live in a hovel if he'd loads of cash. Maybe P O'Neill demanded his bank account be swollen by some MI5 money?

Sources say Donaldson's wife hasn't disowned him and visits the cottage. Some informers are airbrushed out of their family history, but Donaldson hasn't been. The couple's Belfast home has just gone on the market so they might be planning a new life.

Scappaticci lives in rural Italy.

Thankfully, the wider Donaldson and Scappaticci clans have been let live peacefully in west Belfast. That's in contrast to the extended Notorantonio family, who have been held collectively guilty for the criminal actions of individual family members, and have endured dozens of petrol bomb attacks on their homes.

Sinn Fein has been no better than the British in offering transparency on collusion. Scap and Donaldson were both debriefed at length, but the leadership has refused to inform their base of the facts, despite the fact that Scap sent 'innocent' IRA men to their death as informers.

In ruthless, darker days, Scap and Donaldson would be dead themselves. Instead, they now exist in a purgatory from which there is no redemption.

Working-class nationalist Belfast maintains a strong hold on its inhabitants. Aged 16, Scappaticci was chosen to train for Nottingham Forest football club. Three weeks later, he returned to Belfast homesick. How he must miss his old haunts.

Scap and Donaldson loved money, but they would surely exchange everything they've ever earned to come home with heads held high. That's something they won't ever be able to buy.