26.
His friend never ratted him out. Even when they offered him a deal. Of course, he didn't know who had helped catch him, but Anderson always felt guilty for putting away such a good friend, yet also, a swell of pride in making such an impression. His friend didn't think of him as just another thief, he wouldn't sell out just anyone, he thought of him as someone who had his back, someone to protect. Hypocrisy aside, he was glad to have made such a friend. Don't tell Lestrade. Or Sherlock for that matter.