In 1984, when he was a serving police officer with West Yorkshire Police, one of his colleagues Sergeant John Speed was shot and killed outside Leeds Minster, whilst on duty, when he went to the aid of a colleague.
The incident left a lasting impact on Paul, 55, who decided he wanted to do something to help the national initiative to help build a fitting tribute to all police officers and staff who make the ultimate sacrifice at the National Memorial Arboretum in Staffordshire.
The murder of the officer took place on October 31, which is the day Paul began his challenge as a tribute.
And he completed a triathlon every day until Thursday, even on Christmas Day, Boxing Day and New Year's Day.
Paul, who has lived in Watermead for 20 years, has smashed his personal fundraising target of £10,000 but more money is needed to help build the memorial - so all funds are welcome.
You can donate here: https://www.justgiving.com/fundraising/paul-lander3
Paul has battled numerous injuries, flu and several virus' during his efforts - but he powered through and is now feeling fantastic.
He said: "It's been a tough challenge, but it's nothing in comparison to what the police officers who pull on their uniform face every day.
"The challenges and dangers they face, the public only really hear about when the worst happens."
Most of Paul's triathlons took place at the Nuffield gym in Aylesbury, but he completed several around the country to commemorate anniversaries of the death of police officers locally.
In one instance, the 66-year-old father of a police community support officer who was killed on duty in Manchester even completed part of the triathlon with Paul.
Paul added: "It meant a lot to both of us to achieve something in honour of those who made the ultimate sacrifice. You can't help but be motivated by the support of those officers' relatives, friends and colleagues, which saw me through the tough days.
"It has been important to me to raise awareness of how every single officer and many members of staff willingly put themselves in danger every single day.
"At the beginning the challenge was very daunting. I tried not to think about how many were left, and just ticked them off five at a time."
It was as mental a challenge as it was a physical challenge for Paul, who admitted people were becoming concerned as he contracted Flu between Triathlon 80 to 89.
Chair of the Police Memorial Arboretum Trust and former president of the Association of Chief Police Officers, Sir Hugh Orde, said: "I was really worried that we might end up with Paul's name on the memorial at one stage but he needs to be commended for completing this huge challenge for our charity and he should feel justly proud for what he has achieved.
“Not only has his epic challenge raised a considerable amount of money, it has also raised awareness of the Memorial and the selfless acts of those officers and staff who have given their lives to keep us safe and protect us from harm.”