Two former Ulster Unionist Party MLAs, who resigned over the party's decision to field a joint by-election candidate with the DUP, are to form a new party.

Basil McCrea and John McAllister left the UUP after the party agreed on a joint unionist candidate for next week's Mid-Ulster by-election.

The by-election was caused by the resignation of Stormont Deputy First Minister Martin McGuinness as an MP.

The new party is expected to be established in April.