An SNP MSP has given one his aides an official warning after being alerted to a raft of pro-IRA messages on the staff member’s social media account.

Allan Casey, who works for MSP Ivan McKee, repeatedly wrote “Up the Provos” and praised former members of the terrorist organisation.

He is also linked to a flute band that honours former IRA volunteer Martin ‘Doco’ Doherty.

In a statement released yesterday, an SNP spokesperson said: “The posts in question are from several years before Mr Casey joined the SNP or worked for any parliamentarians.

“Mr Casey acknowledges that these posts were in extremely poor taste and has deleted them. His employer has reminded him of the high standards expected of staff. Mr Casey has been warned about his behaviour and understands that any repeat would be unacceptable."

McKee was elected as the Nationalist MSP for Glasgow Provan in May, while colleague Anne McLaughlin represents a similar seat at Westminster.

Casey, who was a Yes campaigner in Glasgow during the referendum, used to work for McLaughlin and is currently employed as McKee’s “parliamentary assistant”.

He has uncompromising views on Northern Ireland and his Facebook account contains a range of pro-Republican messages.

In April 2012, he flagged up the “Annual Volunteer Martin Doherty Commemoration Weekend Events”, which included a set by the Republican Flute Band (RFB) he is linked to.

In the same month, he wrote: “volunteer martin Doherty rfb no1 real pride of govan, up the provos – sinn fein abu [sic].”

Doherty was an IRA volunteer shot dead in 1994 by the loyalist terror group the Ulster Volunteer Force.

Casey also posted comments reminding people of “band practice” for the pro-Doherty group and asked for help in raising the organisation’s social media profile.

In February 2012, he paid tribute to IRA volunteers Declan Martin and Henry Hogan: “Killed on active service 28 years ago today while engaging in a gun battle with undercover SAS scum.”

Earlier that year, he again wrote “up the provos!” and posted: “Your deeds would shame all the devils in hell – f**k the brits, remember bloody Sunday 30th January 1972.”

In another posting, Casey remembered “Vol [volunteer] Pearse Jordan”, who was killed by a Royal Ulster Constabulary officer in 1992: “A brave son of Ireland We Will Not Forget You.”

All the messages were on Casey’s public Facebook site, which includes pictures of him with First Minister Nicola Sturgeon and her predecessor Alex Salmond.

A YouTube account in the name of “Allan Casey” also features videos of the flute band.

A minute of a meeting of the Dennistoun Community Council in June stated that Casey attended on behalf of McKee and McLaughlin.

The SNP has long avoided commenting on Northern Ireland and has not taken a position on whether it should be part of Britain.

A spokesman for the Scottish Conservatives said: "It is not acceptable for MSPs to employ people who support terrorists. This is highly embarrassing for the SNP - a party which is never slow to complain about standards in opponents. People who voted for the SNP in this area will expect swift action to be taken."