THE tanks were not rumbling over Taipa Bridge; there were no coils of barbed wire being unfurled on Hac Sa beach, and the patrons at Fernandos did not have to pick their way through a minefield before tucking into their curried crab - you would never realise Taipa and Coloane were placed under military rule last week. In what has turned out to be a very peculiar coup, the Governor, General Vasco Rocha Vieira, appointed a 64-year-old retired Portuguese army colonel by the name of Leandro as mayor of Taipa and Coloane, having sacked the civil servant who had been in thejob for four years, Fernando Rosa Duque. As military take-overs go it has been a pretty low key affair. In vain the Macanese listened for martial music on the radio and the announcers on Teledifusao de Macau had not changed into army fatigues to warn residents of the islands to keep to their homes after dark or risk being shot by army patrols. General Vieira had clearly decided there was no need to sandbag his office at the pink and white Palacio, or to ride around with Colonel Leandro in an armoured car with rifle-toting soldiers in escort to cow the population in case some of them were stillunder the illusion tycoon Stanley Ho was in charge. The issue of civil service pensions is the unusual spark that ignited the military ferment. Mr Duque is a former president and co-founder of the Macau Civil Servants Union and a friend of the present chairman, Jorge Fao. Mr Fao is also an elected member of Macau's Legislative Council and he has used his seat there to barrack General Vieira over what he sees as the administration's failure to help guarantee the payment of civil service pensions after the handover to the Chinese in 1999. The Portuguese administration has said it is not legally required to pay pensions to non-contract civil servants and the Chinese have stated they will not pay them to anyone who retires before 1999, leaving about 6,000 people out of pocket, according to Mr Fao. After one stormy session in the legislature last month an ''angry and embarrassed'' General Vieira called Mr Fao to his office and ordered him to drop the issue - which he refused to do. A few days later the governor summoned Mr Duque to his office for a meeting at which no one else was present. According to Mr Fao, General Vieira told Mr Duque he was impressed with his work and that he thought they had a good working relationship - but Mr Duque was fired from his job and the Governor was returning him to his former post within the civil service. UNUSED to industrial relations with a khaki tinge and perhaps relieved he was not facing a firing squad, Mr Duque asked General Vieira the reason why, only to be told there were ''other reasons''. Mr Duque believes his friendship with Mr Fao is the reason behind his summary dismissal, which also flies in the face of General Vieira's undertaking last February to accelerate localisation of the civil service. So far Colonel Leandro, apparently nicknamed ''the Sergeant'', has been tight-lipped about the appointment that has propelled him back into service after ending what appears to have been an unblemished and unremarkable career in the service of Portugal. There have been no edicts to street cleaners on Taipa and Coloane to break from their labours to salute passing military vehicles and there are no reports the newly-laid golf course at the Westin Resort is to be sequestered for manoeuvres. Some Macanese have been comparing General Vieira to one of his predecessors, the autocratic Ferreira do Amaral who ruled the enclave as though it was a military garrison from 1845 to 1849, and whose statue was recently shipped back to Portugal because Beijing objected to its ''colonial symbolism''. Amaral had a similarly acquisitive attitude towards Taipa and Coloane, seizing them from the Chinese in 1847. His triumph was short-lived. Affronted mandarins in Guangzhou put a $20,000 bounty on his head and two peasants lopped it off by the Barrier Gate on a hot August afternoon. No one will wish that fate on General Vieira, and we are sure no nefarious souls have been rattling a collection tin in the union headquarters hoping to accumulate the 1993 equivalent of Amaral's bounty. But Mr Fao is warning of possible retaliation in another form - a strike by the 5,000 pen-pushing members of the union. This Saturday it will hold a mass meeting at which members will decide whether to down tools - raising the spectre of 5,000 civil servants going head to head with the garrison to decide if the pen really is mightier than the sword.