Alex Fergusson said the parliament faced many challenges

He previously ruled himself out of the post, but has now said he would still be able to serve his constituents if elected to the job on Monday.

The MSP for Galloway and Upper Nithsdale was urged by a number of parties to put himself forward.

The move received the backing of Conservative leader Annabel Goldie, who described him as a man of "integrity".

Mr Fergusson, who increased his majority in the election, is the only person to have so far formally thrown his hat into the ring.

Holyrood will decide on a successor to George Reid in a secret ballot.

I have been both flattered and humbled by the number of colleagues of all parties who have urged me to take this step Alex Fergusson MSP Scottish Tory Party

The larger parties have been reluctant to give up one of their MSPs to the neutral position in a parliament where every vote will count.

Despite his earlier position, Mr Fergusson said he had satisfied himself that he could continue to look after the needs of his constituents and would submit himself as a presiding officer candidate.

The former farmer said: "I have been both flattered and humbled by the number of colleagues of all parties who have urged me to take this step, but my first duty was to ensure that my service to my constituents would not suffer as a consequence of being elected to the post.

"I am fully aware of the many challenges that will face the Scottish Parliament over the coming weeks and months, and it would be an extraordinary privilege to be elected to the presiding officer's role."

Miss Goldie said her party was committed to making devolution work, adding: "I am delighted that Alex has decided to put his name forward.

"He is a man of integrity, intelligence and political maturity, respected by all sides of the chamber and I am delighted to offer him my wholehearted support."