(Adds response from Sports Direct)
By Paul Sandle and James Davey
LONDON, May 26 (Reuters) - British lawmakers have rejected an invitation to visit Sports Direct's headquarters, which the retailer's billionaire founder Mike Ashley had set as a pre-condition for him to appear in parliament to answer questions about workers' treatment.
The lower house of parliament's Business, Innovation and Skills Committee said it would not accept Ashley placing conditions on his attendance.
Ashley had been summoned to appear before the committee on June 7, a request he initially refused, saying the proposal was an abuse of parliamentary process.
He had a change of heart and last week agreed to attend, but only if lawmakers first visited Sports Direct's warehouse in Shirebook, central England, to see employment conditions for themselves.
Committee chairman Iain Wright said on Thursday that business leaders regularly gave evidence to parliamentary committees without imposing conditions.
"This is part and parcel of living and operating a business in a parliamentary democracy," he said.
A Sports Direct spokesman said it was disappointed that lawmakers would not visit its warehouse to see work conditions.
"The Committee are clearly being unfair. Mike will therefore now seek legal advice with regard to his position in relation to June 7," the spokesman added.
Parliament can in theory imprison a person for contempt, though its powers are untested in recent times, according to a government paper published in 2012.
Ashley is deputy chairman of Sports Direct, holding 55 percent of its equity, and also owns Newcastle United soccer club.
The retailer has been criticised for the treatment of warehouse workers at Shirebrook, though it has rejected the charge that it effectively pays some staff below the national minimum wage.
Additional reporting by David Milliken; Editing by David Goodman and Mark Potter