In May last year, Mr Shatter leaked on RTÉ's Prime Time that Mr Wallace had been cautioned by gardaí for using his mobile phone while driving.

The minister later told the Dáil that information about the incident, which happened in May 2012, was given to him by then garda commissioner Martin Callinan. Mr Shatter has since apologised to Mr Wallace.

Data Protection Commissioner Billy Hawkes ruled today that while Minister Shatter was in breach of the Data Protection Acts, he has not committed an offence and will not be subject to any penalty under the law.

Commissioner Hawkes, however, found that Mr Callinan was not in breach of the Data Protection Acts when he gave the information to the Minister for Justice. He said it was the garda commissioner's duty to keep the minister fully informed.

Mr Shatter has 21 days to appeal this decision.