Postcard-sized original artwork after “Sunflowers” being auctioned by the NG27 Italian Renaissance specialist Richard Stemp, a spokesman for the group, told the Daily Telegraph: “Between us we have more than 500 years of teaching experience at the National Gallery.“There are 27 of us, the least experienced of whom has worked at the gallery for 10 years and the longest serving has been there for 45.“We have probably spent more time with these paintings than anybody in the world – even the curators who have other things to do.“Now we can’t use that experience to teach so we’re using it help the legal fund.” After Constable’s “The Haywain” November’s tribunal has the potential to set precedent for workers’ right in the so-called “gig economy”.Last year Uber lost an appeal than its drivers should be treated as workers – rather than self-employed freelancers – and given rights including sick pay and paid leave, and this June a tribunal found drivers for delivery company Hermes were workers entitled to employment rights.But this is believed to be the first such case involving a public entity. The gallery is funded by the Department for Culture Media and Sport. Artists and art lecturers locked in an employment dispute with the National Gallery are raising money for their legal fight by selling original artwork inspired by paintings hanging on the walls of the gallery.Their paintings ‘after’ some of history’s greatest artists – including Van Gogh, Caravaggio, Leonardo, Holbein, Cezanne and Constable – are being auctioned on Ebay to pay for a ten-day industrial tribunal scheduled for November.Among the postcard-sized artworks in the auction are a close-up of two sunflower blooms, after Van Gogh, a pencil sketch of the Virgin and Child, after Titian, and a moody black and white charcoal after Constable’s The Haywain.Around £3,000 has been raised across the current auction, and another held last month. The funds have been added to £37,000 raised so far through a funding campaign on the website Crowdjustice. Members of the group protesting outside the National Gallery She said: “It is our understanding that the claims have arisen out of the Gallery’s wish to change from offering ad hoc work to offering more secure employment, with additional pension and worker benefits.“This change reflects the Gallery’s strategy to develop our programmes to increasingly reach new audiences and make the most of digital technology to widen our engagement.”She said the group had been consulted over a three month period and had been offered jobs, adding: “The Gallery is not yet in receipt of the details of each complaint, but believes that we have acted both lawfully and fairly in changing our service provision to one of secure employment.” After Titian’s “Virgin and Child” The “NG27” allege that despite working regularly at the gallery for years, teaching school groups and lecturing on artworks, they were unfairly dismissed last October by the gallery which claimed it was simply ceasing a freelance arrangement.They say they were on the gallery’s payroll with tax deducted at source, wore staff passes, were required to attend team meetings and received formal workplace performance reviews; but were dismissed in a meeting at which around a dozen staff jobs were offered to around 45 lecturers.Some of the 27 alleging unfair dismissal continue to work at the gallery on casual contracts.Mr Stemp said: “There would be weeks I worked seven days and other times less. But I relied on that work and they relied on me.”A spokeswoman for the National Gallery said it had received “a number of different claims from a number of freelance workers” and said the majority of claimants continued to work at the gallery. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.