One of the Observer’s leading journalists has branded the Guardian Media Group as “monopolist” after claiming more than 70 journalists have been “given notice” on their contracts following the sale of the newspaper.Carole Cadwalladr, who was nominated for a Pulitzer Prize for her coverage of the Cambridge Analytica scandal, has said her contract is to be cancelled without a pay-off after 19 years working at the publication.It follows a deal being signed last week for the Observer, the world’s oldest Sunday newspaper and sister title to the Guardian newspaper, to be sold to Tortoise Media by GMG, as part of plans to shake up the Sunday publication with a new website and daily digital content.Ms Cadwalladr claimed on X that “freelance” and “casual” staff had been offered to “go to Tortoise on a one-year contract, with no guarantees after, or bye bye.