Norman Baker, MP for Lewes, said the US-based multinational had shown a lack of concern for the environment and for public opinion.
In a debate on the World Trade Organisation, Mr Baker said the firm's activities must be curtailed. "Monsanto are public enemy number one. They insist on thwarting consumer choice, bulldozing elected governments and forcing their wretched products on the world's population. They need to be brought within democratic control urgently.
"Monsanto could well be the bad news story of the 21st century if they are not stopped."
Mr Baker attacked the company for its "intimidating" tactics against farmers, including the use of private investigators to ensure they were meeting its contractual requirements. One firm of US investigators had been hired to question farmers and take samples from their land, Mr Baker said.
The US government was acting on behalf of Monsanto when it warned it would file for damages if the European Union continued to ban the firm's treated milk, he added. Farms in the US that attempted to label untreated milk were threatened with legal action.
In one of its most "cynical" moves to date, the firm had persuaded politicians and leaders in Africa that its technologies were a way to combat starvation. In India, some GM crops were grown without the farmers' knowledge until complaints led to an injunction being granted by the supreme court. Plans to grow GM soya in Brazil this year would substantially reduce world supplies of conventional soya, Mr Baker added.
In Britain, Monsanto had launched a pounds 1m advertising campaign that had made claims later condemned by the Advertising Standards Authority as "wrong ... unproven, misleading and confusing".
Mr Baker also listed a number of examples to support his claim that company executives seemed to be in a "revolving door" to and from official government positions.Reuse content