Back in November 2011 I visited Bunawan in the Philippines to provide independent verification for the length of Lolong, a reportedly "6.4 m" saltwater crocodile (Crocodylus porosus) which had been captured in early September. I was asked to do this by Natural History New Zealand and National Geographic for several reasons, one of which is because I'm quite skeptical about reports of giant crocodiles. It was clear from the photographs and footage that Lolong was a large crocodile, but actually putting a tape measure against it was going to be the ultimate test.
In front of the assembled news media, several hundred visitors, local officials, members of the Palawan Wildlife Rescue and Conservation Center (PWRCC), Protected Areas and Wildlife Bureau (PAWB) and others, I was filmed measuring Lolong accurately using two different methods. The result of that filming will appear in a National Geographic documentary to be aired in the fairly near future, although I don't know the precise date unfortunately. Animal Planet has already aired a documentary about Lolong which they filmed after ours, but the Nat Geo show will show the actual official measurement.
In the meantime, Guinness World Records have accepted my measurement and the evidence provided by National Geographic, and declared Lolong the largest crocodile in captivity at 6.17 m (20.24 ft, or approximately 20 ft 3 in). Here's a photograph of the certificate to prove it: