Atlas of the Counties of England
The North and South Parliamentary Divisions are distinctly coloured, but the whole map has a very "flat" and dull/over-crowded appearance. The choice of railways shown is very erratic, so the date is rather an estimate.
Other examples of this map are 1885 and 1900. More details on Philips's maps are on the Publisher's page.
Scale correct at 6 miles = 43mm, or 3.5 miles/inch, ie 1:220,000.
Two symbols are used on the map for railways, but the key only expains one of them. Assuming the second, more manual looking one is for "proposed" railways, these show Loughton to Ongar and Sudbury to Bury St Edmunds (both opened 1865) but not Audley End to Saffron Walden or Shelford via Bartlow to Haverhill (also both opened 1865); there are Wivenhoe to Brightlingsea and to Thorpe-le-Soken (opened 1866) and on to Walton-on-the-Naze (opened 1867), plus a mythical one from Mistley to Thorpe-le-Soken; Bishops Stortford to Braintree is shown (opened 1869), but not Saffron Walden to Bartlow (opened 1867).