However, by 15 November 1643 Parliament was fruitlessly summoning Littleton back from leave of absence.
By 2 December the tone had become insistent, as Parliament ordered: "That Sir Edw.
Littleton be summoned to attend the Service of the House forthwith."
In January 1644 he joined the Oxford Parliament and on 4 March was disabled from attending Westminster, together with Sir John Borlase, 1st Baronet, "for neglecting the Service of the House, and going to the other Party."
However, it was not until 31 July 1646 that the writ was moved for by-elections to replace both Littleton and Sir Hervey Bagot, a committed royalist disabled as early as 24 November 1642, as Staffordshire MPs.

Some details of Littleton's defection came to light in December 1649, during an investigation into allegations that Basil Feilding, 2nd Earl of Denbigh, the Parliamentarian commander in the Midlands at the time, had been implicated in moves to create a third force or a large scale defection to the king.
These grew out of long feud between Denbigh and the Shropshire parliamentary committee, whose leader Humphrey Mackworth, had discovered Denbigh was in contact with a royalist agent in December 1643.
This came to light through the investigations of John Swinfen, a Staffordshire Presbyterian who later represented Stafford in the Long Parliament, and a Captain Stone.
Denbigh himself admitted to Mackworth that a Captain Gower, who had travelled widely with him, had been encouraging him to go over to the king and that his defection would be accompanied by a royalist rising in Huntingdonshire.
Littleton had announced in Staffordshire that he was raising forces on Denbigh's behalf, apparently in order to launch a third party, with the help of Sir Walter Wrottesley and Gerard Scrimshaw of Aqualate Hall.
Swinfen, a member of the Staffordshire parliamentary committee, had warned that Littleton had made his peace with the king, precipitating his flight to Oxford.
Correspondence between Littleton and Denbigh was said to cast serious suspicion on the Earl, who nevertheless survived this investigation, as several others, and never actually deserted Parliament.

Isolated from his Staffordshire base, Littleton was impotent to contribute to the royalist cause in the area, and parliamentary soldiers occupied Penkridge in 1645 after the briefest of skirmishes.
He served to the bitter end of hostilities in the Midlands: the siege of Worcester, which began on 21 May 1646 and ended on 23 July.
Littleton heads the list of knights present in the garrison at the end of the siege.
However, by 15 November 1643 Parliament was fruitlessly summoning Littleton back from leave of absence. By 2 December the tone had become insistent, as Parliament ordered: "That Sir Edw. Littleton be summoned to attend the Service of the House forthwith." In January 1644 he joined the Oxford Parliament and on 4 March was disabled from attending Westminster, together with Sir John Borlase, 1st Baronet, "for neglecting the Service of the House, and going to the other Party." However, it was not until 31 July 1646 that the writ was moved for by-elections to replace both Littleton and Sir Hervey Bagot, a committed royalist disabled as early as 24 November 1642, as Staffordshire MPs.
Some details of Littleton's defection came to light in December 1649, during an investigation into allegations that Basil Feilding, 2nd Earl of Denbigh, the Parliamentarian commander in the Midlands at the time, had been implicated in moves to create a third force or a large scale defection to the king. These grew out of long feud between Denbigh and the Shropshire parliamentary committee, whose leader Humphrey Mackworth, had discovered Denbigh was in contact with a royalist agent in December 1643. This came to light through the investigations of John Swinfen, a Staffordshire Presbyterian who later represented Stafford in the Long Parliament, and a Captain Stone. Denbigh himself admitted to Mackworth that a Captain Gower, who had travelled widely with him, had been encouraging him to go over to the king and that his defection would be accompanied by a royalist rising in Huntingdonshire. Littleton had announced in Staffordshire that he was raising forces on Denbigh's behalf, apparently in order to launch a third party, with the help of Sir Walter Wrottesley and Gerard Scrimshaw of Aqualate Hall. Swinfen, a member of the Staffordshire parliamentary committee, had warned that Littleton had made his peace with the king, precipitating his flight to Oxford. Correspondence between Littleton and Denbigh was said to cast serious suspicion on the Earl, who nevertheless survived this investigation, as several others, and never actually deserted Parliament.
Isolated from his Staffordshire base, Littleton was impotent to contribute to the royalist cause in the area, and parliamentary soldiers occupied Penkridge in 1645 after the briefest of skirmishes. He served to the bitter end of hostilities in the Midlands: the siege of Worcester, which began on 21 May 1646 and ended on 23 July. Littleton heads the list of knights present in the garrison at the end of the siege.
Sir Edward Littleton, 1st Baronet