Celtic are working intently on signing a marquee centre-back and want a deal done in the next week, Football Insider understands.

The Hoops are short of cover in central defence after allowing Jozo Simunovic to leave when his contract expired at the end of May.

A Celtic source has told Football Insider that Neil Lennon has made it clear to the hierarchy he wants another senior and proven defender to strengthen his back line.

However, the new arrival is set to be a loan move only rather than a permanent deal.

Preliminary talks have been held been Brighton’s Shane Duffy but Celtic face significant competition for his signature from Premier League clubs.

West Ham, Sheffield United and newly-promoted West Brom are all keen on the Republic of Ireland 28-year-old.

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The Hoops have already made two major signings this window and will need to sell before they buy any more.

Striker Albian Ajeti joined from West Ham yesterday for an initial £4.5million rising to a potential £6m and goalkeeper Vasilios Barkas arrived from AEK Athens last month for £4.5m.

Lennon regards a new centre-back as his next priority to provide cover and competition for first-choice pairing Christopher Jullien and Kristoffer Ajer.

The only other senior centre-back on the club’s books is Nir Bitton, althoug Hatem Abd Elhamed can also switch from his favoured right-back slot to a more central role.

In other news, a Celtic star will be key to Leeds United signing their “No1 priority target” this summer.