A gold ring that may have belonged to a member of Guy Fawkes' Gunpowder Plot is set to spark a bidding war - with experts expecting it to fetch up to £12,000. 

The 16th-century band, engraved with the chilling message "Yovr Frende in Deede" (Your Friend in Deed), was dug up just yards from the birthplace of plot mastermind Robert Catesby. 

The inscription is thought to symbolise loyalty in action and could be a nod to the deadly plan to blow up Parliament on November 5, 1605. 

Experts say the phrase is unheard of on similar posy rings from the era, and could point to a secret bond between the Catholic rebels who plotted to kill King James I. 

The ring was unearthed by metal detectorist Andrew Rose, who found it six inches deep in a freshly-ploughed field near Bushwood Hall, near Warwick, where Catesby was born. 

Andrew said: "The hall where Catesby was born can only be accessed down a track which means it is even more likely the ring, which was found only yards from the moat, was connected to the hall, or was owned by someone who lived there.  

"The words 'in deede' suggest whoever gave the ring was prepared to prove his loyalty in actions rather than just words. It was a great find and hugely exciting." 

At the time the hall was a weapons stash and hideout for the gang - including John Wright, a close ally of Fawkes who went to school with him in York. 

The plot was foiled by a mystery snitch, who warned a lord to steer clear of Parliament. 

Fawkes was caught red-handed in a cellar and later hanged, drawn and quartered. 

Catesby and the Wright brothers were gunned down by the King's men days later in South Staffordshire. 

The ring is expected to sell for between £8,000 and £12,000 but could fetch far more when it goes under the hammer next month.  

Auctioneer Charles Hanson said: "Guy Fawkes, Catesby and their network – many of whom were related by blood or marriage – moved between safe houses in the Midlands.  

"They were protected by the region's large Catholic base who were, like them, against the king.  

"Given the remoteness of the hall's location, its link to Catesby, the date and inscription of the ring, it is tantalising to imagine it belonging to one of the plotters.  

"Imagine it glinting by firelight as they planned one of the most audacious attacks in UK history." 

The ring will be sold at Hansons Auctioneers in Etwall on November 12.