The painting Self Portrait As A Young Man dates back to 1629

Rembrandt expert Professor Ernst van de Wetering said the 1629 painting, Self Portrait As A Young Man, was probably painted by a pupil of the Dutchman.

He said the work, which has hung in Liverpool's Walker Art Gallery for the past 50 years, is "primitive".

A spokesman for the Walker Art Gallery said the professor's view was an "opinion amongst many".

"The Walker Art Gallery's curators believe that in its present condition it is not feasible to make such a firm judgement on its painting, which is covered in a heavy discoloured varnish that obscures both original brushstrokes and old re-touchings, and has probably not been cleaned for at least half-a-century," said the spokesman.

'Star pupil'

"It considers that the view is not a definitive judgment but merely one opinion amongst many that the Walker Art Gallery takes into account when displaying and interpreting its paintings to the public."

Prof van de Wetering, who is chairman of the Rembrandt Research Programme, said it shows "a fundamentally different pictorial approach from that of Rembrandt".

He suggested the real artist of the self-portrait was a star pupil of Rembrandt's, Isack Jouderville.

He said: "The alternative suggestion that there must have been another hand at work, and a rather weak hand at that, is irresistible."

'Classic example'

Making the claims in his book, A Corpus of Rembrandt Paintings Volume IV, he also casts doubt on the authenticity of two other paintings by the artist, Young Man in a Turban, and An Old Woman.

Both paintings belong to The Queen's Collection.

Self Portrait As A Young Man shows the artist in a black velvet beret with furred habit, scarf and chain.