Lowry is famous for his Matchstick men and matchstick cats and dogs and became the obsession of Newmarket businessman AJ Thompson, filling the walls of his house in Six Mile Bottom.
After his death, last summer, his impressive collection passed to his sister Dawn Sadler who is now selling the collection.
"Lowry was a man who walked around in an old raincoat and didn't give a damn about anyone. Did his own thing. And that's what he did. He thought I like this man. I like the story of this man. I'll buy a painting and then of course it became a collection. Like people collect egg cups, he collected paintings. But luckily they were worth more than when he bought them."
It's thought one painting alone, Piccadilly Circus, will sell for as much as 6 million at auction at Southeby's.
Dawn told Anglia News her brother's life was a true tale of rags to riches.
Tony Thompson started his waste paper business when he was just 14 but went on to become a multi-millionaire.
He started just knocking on doors asking for paper very much the beginning of recycling.
Despite being a multi millionaire Mr Thompson drove everywhere in a Brown Ford Fiesta.
Many people thought he was a tramp because he held his trousers up with string and they certainly never guessed he had modern masterpieces hanging on his walls.