Milton Ernest did not have an official mail service or post office until 1843. Before then letters would have been put into the post at, or collected from, the Post Office at Bedford. This was initially on the corner of the Fish Market, but in 1835 moved to the old Toll House at the foot of Bedford Bridge, where it remained until 1855. Letters for collection would have been displayed in the Post Office's windows.

An unsuccessful application was made to the General Post Office in 1841 to establish an official post to serve Bletsoe and neighbouring villages, including Milton Ernest. In April 1842 leading inhabitants offered to guarantee the cost of providing a post (£107 a year). From 1843 the Post Office established a daily mail cart service from Bedford to ‘receiving offices’ (in effect, sub-post offices) at Milton Ernest, Bletsoe, Sharnbrook, Odell and Harrold. William Solesbury was the village's ‘receiver’ (sub-postmaster) from May 1843 on an annual salary of £3. There was no official delivery of post in Milton Ernest until 1854, when the sub-postmaster was paid an additional £2 a year to provide a delivery.

Letters were despatched from Bedford either by the evening mail cart to London thence via Falmouth packet, or later by north-bound Mail Coach or train to Liverpool, and thence by monthly mail packet (initially sailing vessels, then steam-driven) to New Brunswick. Letters could take six to eight weeks to reach their destination. One letter, postmarked ‘BEDFORD’ on 1 August 1840, arrived in New Brunswick on the 13 September. A later letter sent from Bedford on 1 October 1844, arrived in St Andrews on the 22 October. There are frequent references in the Turner correspondence to the loss of letters.

Postage was expensive (see table below), depending on the distance carried inland, destination and number of letter sheets (John Turner always used one, closely-written sheet). Rates were complicated and subject to changes. For example, in 1831 letters for America and British North America were made up in London for the monthly packet, charged the standard packet rate plus the inland post rate to London less 2d. This was reduced to a 1/– packet rate for letters weighing up to ½ ounce to British colonies from December 1839 – which is alluded to in one of John Turner's letters.