The City Slickers claimed colleagues knew what they would be tipping

The new guidelines will strengthen the code. They have also helped persuade the government not to bring in legislation, which would have forced journalists to declare their financial interests.

The chairman of the PCC, Lord Wakeham, said: "I hope all editors will look at its terms and examine the internal procedures of their own newspaper or magazine in this area accordingly.

"That way we will be able to raise standards across the board, protect the consumer interest and ensure that the reputation and integrity of financial journalism throughout the industry is enhanced."

The new guidelines follow talks with the government and the Financial Services Authority.

Government talks

The PCC launched an inquiry into share dealing by journalists at The Mirror after it emerged that a number of staff had bought shares tipped in the City Slickers column.

Journalists Anil Bhoyrul and James Hipwell had personally profited by buying shares then tipping them in their pages, sending the price rocketing, and then selling the shares at a profit, the PCC said.

Mr Hipwell had done this on 25 occasions, Mr Bhoyrul on 16.

The PCC concluded that Mr Bhoyrul and Mr Hipwell "engaged in flagrant, multiple breaches of the code of practice over a sustained period time".

It also ruled that Mirror editor Piers Morgan breached the code and had fallen short of the high professional standards it demanded.

The commission said Mr Morgan had known about Mr Hipwell's trading in 1999 and while he had warned the journalist verbally, he did not do enough to stop it happening again.

Paper fortune

But The Mirror editor later tried share dealing himself.

He bought shares in Wiggins Group as well as �20,000 worth of Viglen Technology shares the day before the City Slickers page tipped the company.

Shares in Viglen jumped when the report was published, boosting Mr Morgan's paper fortune.

Although Mr Bhoyrul initially backed his editor's claim that it was a coincidence, the former City Slicker later changed his tune.

He said Mr Morgan knew the shares would be tipped, but the Mirror editor denied the allegations.

Mr Morgan, who was cleared by an internal inquiry by the newspaper's owners Trinity Mirror, later sold the Viglen shares and promised to give his profits to charity.