The trenches for the southern outfall sewer scheme were monitored, between 1979 and 1980, especially at points where they were to cross the lines of known ditches. Crummy records, 'As far as possible the trenches were carefully monitored especially at points where they were to cross the lines of known ditches. The trenches were usually shored as soon as they were dug so that sometimes parts of the trenches could not be properly examined. However the watching brief provided firm fixes - in Parr Drive, Oaklands Avenue and Straight Road - on ditches previously known from aerial photographs. Of special note was the discovery that the Triple Dyke did not reach Heath Road. Also the absence of features at certain critical points also proved of value. In particular, 40m of the trench at the junction of Shrub End Road and Gosbecks Road was examined especially carefully, and it was clear that Shrub End Dyke does not exist in this area. This raises the question did Shrub End Dyke extend further south than its junction with the Heath Farm Dyke? The trench at Oaklands Avenue contained no evidence that the NW-SE Roman road, known west of Gryme's Dyke as a cropmark extended east of the Dyke. Of the small ditches, two (F8 and F9) may belong to the 'camp' refered to by Morant and others (CAR 11)'.<1> The work demonstrated that the Triple Dyke (MCC7041) did not reach Heath Road. A large ditch (F7), which is probably Shrub End Dyke (MCC7467), was sectioned near the western end of Heath Road, measuring 6.1m wide x 3.2m deep (MCC8063). Also, it was shown that Shrub End Dyke [MCC7467] does not exist at the junction of Shrub End Road and Gosbecks Road.<1> Along Straight Road, three features (F1, F2 & F3) were defined in the 100m section of trench north of the junction of Straight Road and Dugard Avenue. Kidman's Dyke (MCC7283) was sectioned and one possible ditch was noted. The next 200m strecth of trench south of Kidman's Dyke revealed three small ditches (F8, F, 9 and F10, the latter being modern). Note that the trench should have cut across Heath Farm Dyke Middle (MCC2095) in the area of F9 and F10. A ditch F2 was defined across the trench at the NW corner/bend of Oaklands Avenue (TL 96415 23951). Along Parr Drive, a N-S ditch (F2) was cut by the SE angle of Parr Drive, which is possibly the same ditch F2 as that encountereed at Oaklands Avenue and Straight Road. NB. This would mean the ditch was aligned NW-SE, and make it (almost certainly) the 'Laver ditch' (MCC10054). Also along Parr Drive, a N-S ditch (F6), c.5m wide x at least 2.25m deep was defined in two places at Parr Drive (TL96471 23914)and once at the junction of Parr Drive and Dugard Avenue (TL96493 23809).