The special 90-minute episode - the first in a new 20-part run - was down on the 5.1m (23.8%) who watched the start of the last series on October 11, 2007.
ITV1 won the 8pm hour on Wednesday with The Bill, which took 5.58m (22.3%). On Channel 4, a new series of Relocation, Relocation started with an impressive 3.13m (12.5%) and Five's Ice Road Truckers brought in 1.69m (6.7%).
BBC Two had 2.1m (8.5%) for a new run of It's Not Easy Being Green, then the latest Masterchef appealed to 2.29m (9.1%).
A repeat of Taggart pulled in 4.2m (17.4%) to ITV1 in the 9pm hour and on BBC One at 9.30pm, benefit fraud documentary On The Fiddle? had 4m (17%).
Five movie Murder at 1600 averaged 1.17m (5.8%) between 9pm and 11.05pm.
Rick Stein's Memoirs Of A Seafood Chef, a 90-minute profile of Stein's 30 years in the business, delivered 2.38m (10.4%) to BBC Two from 9pm. On Channel 4, the latest update from Celebrity Big Brother logged 2.95m (12.3%) and 330k (2.1%) on Channel 4+1.
Coronation Street took the day's best numbers, notching up 9.54m (41%) for ITV1 at 7.30pm. It was preceded by Emmerdale, which put in a strong 7.77m (35%).
Hollyoaks managed 1.66m (7.8%) for Channel 4 at 6.30pm, then 803k (4.1%) for E4 at 7pm (122k, 0.5%). On Five, Neighbours had 1.44m (8.6%) and Home & Away had 1m (5%).
ITV1 kept the lead in primetime with a steady share of 22.9% (last week: 22.8%) to BBC One's 17.7% (21.9%). Channel 4 crept from last to third place with 9.3% (5%), pushing BBC Two to fourth with 8.9% (9.9%). Five was last with 5.2% (5.7%).
Ratings data supplied by Attentional