Trail from Tilbury train station to Leigh-on-Sea train staion via Tilbury Fort, Coalhouse Fort, Hadleigh Castle and vaious nature reserves along the South Essex Marshes. The trail passes historic sites, industrial areas, nature reserves - mud flats and salt marshes, which are great for birds - and marinas. Lovely views of Kent and along the Thames.
Full description on the TEP website (http://www.thamesestuarypath.co.uk/ and another good guide https://www.caminoadventures.com/blog/thames-path/). Please note this states the trail as 29 miles, but I followed the trail precisley from Tilbury station to LoS station and my watch measured 27.0 miles. The trail is very well marked most of the way (it was only opened in 2014) but I took a couple of wrong turns and a short detour or two. There are three railway crossings to make and a couple of fields which might contain bulls.
Weather was warm and dry, path surface was dry.