Mr X mystery and Britain's biggest drugs haul.

Labour's shadow paymaster general Dawn Primarola is warning that Government cuts in Customs and Excise staff will turn the Highlands and Islands into the front door to Europe for international smuggling, not just the back door.

She fears the anti-smuggling teams in the North and West of Scotland could be down from 40 officers to just six. The promise of five "fire brigade" teams being on hand for fast-response action does not impress either Ms Primarola nor the customs union the Public Services, Tax and Commerce Union who are comitted to opposing the proposed cuts. JOHN VASS investigated the biggest drugs haul ever and the big Customs and Excise operation which cost millions to mount but flopped because of lack of manpower. Here he recalls what happened and the clear message that today the Scottish Office appear to have forgotten ...

Britain's biggest drugs haul - about half a ton of uncut cocaine worth 101.5 million was being driven down tortuous West Highland roads on a snowy January night in 1991 and would have been delivered to its London underworld network but for an alert Ullapool police officer.

The consignment had slipped through the Customs and Excise net although it had been known weeks before that a huge quantity of top-grade South American cocaine was on its way to the North West of Scotland. Reports of the case refer to the 18-month Customs and Excise operation which foiled the operation. But the truth is that had the couriers not decided to have a late night or early morning stop in a car park 12 miles south of Ullapool where their van aroused the suspicions of a police sergeant, Customs and Excise would have been left with egg on their faces in a big way.

The van was not the one Customs officers had been tipped to watch although they did have the identities of three local suspects. The consignment was brought ashore on December 22, 1990 and hidden on a tiny island visited only by salmon and shellfish fishers. It remained undiscovered for a full fortnight despite the fact that Operation Klondyke had brought a high degree of Customs activity to the area. And it must be remembered the drugs were not delivered in some high speed launch that flashed in and away, but in a foreign 200-ton rust-bucket of a tramper, the Dimar-B, whose Spanish skipper Francisco Torres, was extradicted from Canada some months later.

But all this is not aimed at criticising Operation Klondyke but highlighting the near impossible task of policing hundreds of miles of remote and rugged coastline with a few Customs officers and a handful of police who have more basic duties than chasing after suspect smugglers.

Following the 6 million consignment of cocaine found on a South Uist beach earlier this month, the timing of the Scottish Office proposals to trim Customs staff in the West Highlands is unfortunate. Western Isles MP Calum MacDonald has described the proposal as being "hypocritical beyond belief" coming from a Government pledged to fight the drugs menace. Many agree because they are aware just how vast is this door - be it back or front - to both Britain and indeed Europe.

Why pick West Sutherland to land 101.5 million of cocaine? Because the big Columbian cartel which supplied the drugs had contractors who convinced them they had done their homework and knew the chances of detection were extremely minimal. Right now the population of Ullapool will have swelled to double the normal with visitors and being on the lookout for drug smuggling will not be forefront in their mind. Operation Klondyke was a major exercise launched in 1989 involving police and teams of Customs officers, deployed all along the western coastline. How many safe landings of drugs has been caried out is anybody's guess.

That the 101.5 million consignment of drugs had been driven through this popular little tourist village in a battered orange-painted Ford transit with Baxter's self drive, Forfar, on the sides, without arousing anyone's suspicion only emphasises the difficulties of detection. Had not the sharp-witted Michael MacLennan become curious as to why the van should be parked in the snow-covered tourist car park at the Corrieshalloch Gorge and alerted his headquarters in Inverness, the drugs would have got to London as planned.

Indeed the van had completed three hours of its 13-hour journey when police stopped it on the A9 near Kingussie. It was there Customs saw for the first time that the van contained 25 neat labelled waterproofed packs addressed to Professor Davidson, Department of Geophysics, University College, London . (There was no such person). Each pack was labelled ''inert samples, Atomic Energy Authority, Dounreay''. It was a neat operation which nearly came off..

Today the Government are particularly vulnerable to criticism because of their apparent concern for politically influential landowners concerned with curbing poaching on their Highland estates. Yet the greater concern should surely be the curbing of drug smuggling. Uninhabited islets, secluded inlets and accessible bays pepper the whole of the west coast making it a smuggler's paradise.

While Customs and Excise put on a brave front with high speed launches, they admit they are starved of manpower and the prospects of improvement fairly slim. The Government are party to this deception. When the massive haul of cocaine was traced, a Treasury minister gave the full credit to Customs and Excise while the police officer whose alertness led to the van being detected was, in contrast, sent a letter of commendation from his chief.

Just how Basque sea captain Francisco Torres managed to sail the 300-ton Dimar-B close enough inshore for the cargo to be unloaded on to an inflatable dinghy without being spotted is a further unsolved mystery. The answer has not been revealed by Torres, now serving a 30-year sentence for his part in the exercise. It was the longest sentence of the six imposed in connection with the haul. Three Ullapool men and two from Dundee got sentences totalling over 70 years. At the High Court hearing of the case, the judge ruled the identity of the mastermind who was on the run in Spain should be identified only as Mr X. But in 1992 Spanish police arrested Mr X on an Interpol warrant in connection with the drugs haul. Several months later an extradition order was granted but just before he was due to be returned to Britain he escaped while he was being transferred from Alicante to Valencia's high security jail.

Now three years later he is still on the run. The warrant for his arrest is still in force but the chances of him being picked up again must be unlikely. Yet the identity of the man believed to have masterminded the operation for his Colombian boss remains Mr X so that efforts to effect his arrest are not hindered or his subsequent trial jeopardised.

It is one more situation bordering on the ridiculous because his identity is well known in the Highlands. It is understood that as a youngster he helped his parents run a hotel in the Victorian Spa village of Strathpefffer then after training as a diver worked on several North Sea oil rigs before turning to drug smuggling.

When he was arrested in Spain a Highland police officer went to Spain to confirm his identity. For Mr X was a resident in the Ross-shire market town of Dingwall before setting up an olive oil export business on the Costa del Sol.

Yesterday a spokesman for the Crown Office confirmed that there was an outstanding warrant for the arrest of Mr X and so the legal position remained unchanged.