Was the Loch Ness monster chubbier than we thought? 1936 sketch of giant beast seen in famous Scottish waters is revealed after top secret 'Monster Files' are published for first time
· Sketch convinced 'staggered' natural history expert that monster could be real
· The drawing is among hundreds of papers in batch of 'Monster Files' papers
· They were publicised this month by National Museums Scotland
· Sketch produced after 1933 news article brought creature to global attention