The annual season from Manningtree to London is £4,400 (£5,040 with a Travelcard). Assuming you pay 40% tax as a lot of commuters do, you need to earn £7,333 (£8,400 with Travelcard) just to buy your ticket.
An annual car park ticket at Manningtree costs £960 which would require you to earn £1,600 before tax to pay for it.
So if a couple commute to London, require a Travelcard and park at Manningtree they have to earn £18,400 between them just to cover the cost of travelling!
The numbers for those paying 20% tax are as follows:
Season ticket - £4,400 (£5,040)
Needs to earn £5,500 (£6,300)
Car Park - £960
Needs to earn £1,200
When taking into account that people on 20% tax are earning less than £34,800 that is quite a sizeable chunk of income going on the cost of travel.
Of course, it should be mentioned that all the above assumes that individuals can fork out for an annual ticket. Monthly, weekly and daily tickets obviously cost more over a 12 month period.