THE owners of the Grangemouth petrochemical plant have asked ministers to make it illegal for unions to intimidate senior executives during industrial disputes.

Last year the Unite union faced allegations it tried to bully managers at the petrochemical plant and their families, using a tactic known as "leverage".

The union was accused of sending protesters to the homes of Inoes staff.

At the time David Cameron called the accusations shocking, saying: "No-one has a right to intimidate, nobody has a right to bully, nobody has a right to threaten people's families, no-one has a right to threaten people in their homes."

Ineos, the world's fourth largest chemical company, has now asked the Coalition Government to make it a criminal offence for trade unions to "intimidate and bully" individuals.

In a submission to the Carr Review into union tactics which Mr Cameron ordered after the Grangemouth allegations, Ineos also wants the strike notice period to be extended from a week to three weeks to limit what it says are safety risks for plants such as Grangemouth.

It also wants unlimited damages available for illegal action targeting individuals, suppliers and customers.

Jim Ratcliffe, chairman of Ineos, said: "We cannot tolerate the thuggish intimidation of managers, suppliers and customers by out-of-control unions.

"Last year, one of UK's largest industrial sites nearly closed down because of reckless union actions."

A Unite spokesman said: "We are extremely disappointed that while we strive hard to rebuild relationships at Grangemouth, the CEO of Ineos is engaging in [a review that] is little more than a political stunt."