Henry Vincent, 37, died following a struggle with Richard Osborn-Brooks, whose home he invaded in the early hours of April 4.
Mr Osborn-Brooks was initially arrested on suspicion of murder but was later released without charge.
The pensioner's arrest provoked a public outcry, and an online fundraising campaign in support of the pensioner subsequently raised thousands of pounds.
A funeral service is to be held today at St Mary's Church in St Mary Cray, south-east London, a police officer at the scene confirmed.
LIVE PICTURESiPhone transfer software
A marked van filled with officers drove past the Church of England building several times, before passing up nearby Star Lane, site of St Mary Cray Cemetery.
Flowers were tied with red ribbons to lampposts around the perimeter of the churchyard, reminiscent of tributes left by Vincent's loved ones near the scene of his final crime in Hither Green, south-east London.
Concern has been mounting that the intruder's final send-off could descend into an ugly confrontation between the bereaved and supporters of Mr Osborn-Brooks.
And today, concerns were proved right as, in fiery scenes, mourners flicked the V-sign at crowds of onlookers and members of the press.
Another group arrived at the church in Orpington and threw eggs.
SWNS - PAHither Green funeral: The funeral procession has begun
SWNSHither Green funeral: Police tackle a person who tried to attack the press
Photographs later showed a police officer tackling a man to the ground before other officers rushed to help detain the suspect, who allegedly attempted to attack journalists.