The 31-year-old beauty embarked on a trial separation with the 43-year-old comedian in February, but she has now left their mansion with their son Alfred, two, and dog Bert, appearing to put an end to their five-year marriage.
A source said: ''The fact she's moved could suggest the marriage is definitely over.''
Lara has since moved to an upmarket London area, which is just three miles away from the marital home but the new house is ''a lot smaller'' than the mansion she lived in previously.
The source added to The Sunday People newspaper: ''Lara's new place is a lot smaller than the huge mansion she shared with David but she seems to be enjoying life and is often seen having breakfast in a local cafe.
''The home is not as grand as people might expect but it has a lovely, traditional feel about it and it's in a lovely part of town.''
Lara and David - who tied the knot in 2010 - are said to have not made any formal or financial agreements about a split yet.
However, the 'Britain's Got Talent' judge was seen without his wedding ring for the first time, with insiders insisting he has accepted his marriage is over.
A source previously said: ''David was holding out hope that he and Lara would stay together. But after going to America this month he realised he needs to try and move on. This is the first step in that direction.''