The past few months have seen 10,152 acute outpatient appointments and 1,710 elective procedures postponed at the most affected trusts - King's College Hospital NHS Foundation Trust and Guy's and St Thomas' NHS Foundation Trust - as a result of the attack.

One of the final pieces in the jigsaw was the reconnection of blood transfusion laboratory IT systems. The trusts have now moved back to being able to issue all blood group products for transfusions. While some important administrative work remains, any further impact on patient care will be minimal.

The amber alert for blood supplies remains in place and new and existing O negative and black heritage blood donors are still being urged to come forward and donate.

NHS Blood and Transplant director of donor experience Mark Chambers said: ‘This has been a tremendous team effort, and we're deeply grateful to everyone who helped restore services. However, rebuilding blood stocks will take some time. We are still under a shortage alert and urgently need O negative and black heritage donors to come forward.'

In a joint statement Professor Ian Abbs, chief executive of Guy's and St Thomas' NHS Foundation Trust and Professor Clive Kay, chief executive of King's College Hospital NHS Foundation Trust, added: ‘The recovery of these services is the result of a phenomenal effort from colleagues who have been working relentlessly to get us to this position and we would like to thank everyone involved for their patience, flexibility and commitment during these challenging months.'

Synnovis chief executive Mark Dollar said: ‘There is still work ahead of us to restore remaining business administrative IT systems within Synnovis, but thankfully we now see light at the end of this tunnel.'