More than 2,000 people attended the service to remember the police officer who was killed whilst working on the roadside in Wallasey, Merseyside, on October 5.
Police officers from across the UK and dignitaries are also attended.
The ceremony for the father of two, 34, will be led by Revd Lyndon Bannon.
A sermon was given by the Bishop of Birkenhead Right Revd Keith Sinclair whilst the Bishop of Liverpool Paul Bayes will give the blessing.
His coffin was draped in a silk cloth with the force's emblem, and was carried from the city's cathedral following the hour long service.
During the service tributes were paid to Pc Phillips who was described as one of the "finest" officers by the Chief Constable of Merseyside Police Sir Jon Murphy.
He told mourners that Pc Phillips had been "a local boy who joined his local force, Merseyside Police, to serve his local community".
He added that the country had been left outraged by the loss of the dedicated and courageous officer.
Two songs were performed to the congregation from the musical Les Miserables - favourites of Pc Phillips and his wife.
Revd Bannon told the Liverpool Echo: "It was important the service was held at the cathedral so the whole community, not just family and friends, could pay their respects.
"It's likely to be a very emotional and moving event as we get together and celebrate all that was good about Dave's life.
"It will also remind us that every time a police officer goes on duty, they are putting their lives at risk for the good of society and for the benefit of us all."
Hymns The Lord Is My Shepherd and I Vow To Thee My Country have been chosen alongside two songs from the musical Les Miserables.
