ACPO lead on criminal justice, Chief Constable Chris Eyre said: "Police bail is an essential tool in securing justice. It allows investigators to ensure every possible avenue is explored, while those arrested need not remain in custody.
"Each and every investigation follows a different path, and detectives will go where the evidence leads them. The huge complexity of some investigations in the 'information age' can mean this takes time. Hi-tech crime investigations, computer forensics, CCTV, telephony, using interpreters or gathering evidence across borders and jurisdictions can all take time and painstaking analysis.
"We would all agree that criminal cases should be concluded as swiftly, justly and transparently as possible. This is important both for victims, and in preserving public confidence in the criminal justice system as a whole. But officers must have the time needed to deal with complex investigations appropriately and thoroughly."