As she talked, Ms Ferraro must have known that police in Britain, Italy, the United States and Costa Rica were secretly preparing the round-up of more than 200 people believed to be involved in a big international drug-trafficking and money-laundering network.
Asked whether she had evidence of Mafia infiltration in Britain, Ms Ferraro said investigating magistrates had uncovered 'relationships between people and organisations' in Britain and mafiosi in Italy but that it was 'inadvisable' to give details. Her staff could not say whether she was referring to the people behind the 43kg of cocaine and the vast quantity of cash found in London, or to others.
Ms Ferraro is the successor of Giovanni Falcone, the Mafia's Enemy No 1, who was assassinated in a car-bomb attack earlier this year. She is pursuing his strategies and methods, which have recently borne fruit in a spectacular series of arrests of top Mafia figures in Italy and abroad.
Her appeal to Britain was also part of her commitment to continue his work: 'The life and death of people like Falcone must have a result all over the world. Otherwise it was for nothing.' Falcone, with whom she had collaborated closely, had taught that one of the main concerns of the international Mafia is to launder the immense profits from its global drug trade. The recent repatriation and arrest of the three Cuntrera brothers, Sicilians who had allegedly run a vast money-laundering empire from Venezuela, and now the break-up of a huge Colombian-Italian-American network, clearly mean that vast sums will be looking for new places to be recycled.
Ms Ferraro believes the City of London is a natural target for Mafia drug profits. She appeared even more concerned about ailing British firms which, unsuspectingly, may be seduced by Mafia cash. 'I give you an example,' she said. 'Your company is in difficulties and I say I would like to give you money. I give you a little money - and later give you a little more. You remain the owner, but when I see you are ready for it, I give you much more - but 51 per cent (of the firm) becomes mine. My money has captured your company and then I can tell you what to do. I can take over other firms like this, one by one, one by one, constantly building up my power.'
A British police source hinted that British firms may already have fallen victim to the Mafia. 'It is being looked at at the moment,' he said.
Ms Ferraro said the danger was great and needed urgent attention. 'It is important to make decisions now.' She suggested that Britain and other threatened countries needed to introduce a law against 'association to commit crimes', which is frequently used in Italy to jail Mafia bosses who mastermind crimes but are careful not to dirty their own hands.
It was also 'the most difficult thing' to identify Mafia money as it moved around the world. 'I don't think existing methods are good enough,' she said.
The police source agreed that Mafia funds are 'bound to head for London', since it was one of the main financial centres of the world. But he said British laws and tracing methods were perfectly adequate to cope with it. There was no need for an 'association' law: a Mafia boss could be charged with conspiracy, he said. And British methods of tracking money were extremely advanced. 'We can trace any funds anywhere. We can trace Mafia money; we are doing it all the time.'
The world's mafiosi may have in Liliana Ferraro a tougher adversary than they think. Behind her blonde hair, her charm, even a touch of coquetry, lies a formidable lucidity, a toughness and, as one newspaper put it, an immense ability to 'mince work'. She does not appear oppressed by the daily danger to her life.
She is presiding over a period of successes against the Mafia which have their origins, she said, in legislation and reorganisation initiated more than a year ago. A crucial factor, was the 'political will' of the Italian government to conduct a more effective war against organised crime, which resulted in the appointment of Falcone to the important post.
The 'supergrass' law, which has resulted in many mafiosi betraying their colleagues, a law permitting the detention of people known to be involved in Mafia activities, the centralisation of police, Carabinieri and other anti-Mafia investigators and the co-ordination of prosecutors all contributed, she said.
But this was not enough. 'I think the legislation can be improved. The Mafia . . . is improving itself day by day, changing its organisation - it changes in many ways. The state's organisation must be effective all the time; it must study day by day how to improve too.'