1. Fry the onion, carrots, celery and garlic until they're soft - probably for about 5 minutes.
2. Add the bacon and cook for another 3 to 5 minutes.
3. Pour off any excess fat from the pan
4. Add the baked beans, tomatoes, red beans and tomato puree.
5. Bring to the boil and simmer for about 5 minutes.
6. Season well with the salt, pepper, herbs and Worcestershire sauce.
7. Use the fat, flour and milk to make a white sauce and stir the mustard and other seasonings you might fancy into this.
8. Fill a greased oven-proof dish with layers of the bacon mixture, the sauce and the lasagne. (Save a little bit of the sauce for sticking on the top at the end.)
9. Cover the top with the sliced egg and the remaining white sauce and a generous sprinkling of cheese.
10. Cook in a fairly hot (200 degrees C / Gas Mark 6) for 30 to 40 minutes - until it's all bubbling and the top has browned nicely.