channel capacity increased. In 2005, the auction for two new slots on National Grid Wireless multiplex D resulted in broadcasters bidding high prices to gain bandwidth. ITV won the bidding for the first slot (on which it launched Men & Motors on 2 May 2005, replaced by ITV Play and later ITV2+1), and Channel 4 the second. Channel 4 launched E4 +1 (not its new channel More4) on the multiplex when the slot became available on 1 June (E4 launched on Freeview on 27 May 2005). National Grid Wireless made an additional new slot available on Multiplex D using the new compression techniques. The 18-hour channel, running from 6am to midnight, became available on 1 December 2005. Companies interested had until 1 November to submit their bids, with bids said to have reached £10 million, from an entry level of £5.5 million, with 12 separate bidders covering all sectors of broadcasting. This slot was won by Channel 4; it was occupied by More4+1 until live coverage of Big Brother replaced it on 18 May 2006. Film4 took over the slot 23 July 2006. Later compression technology, implemented in codecs like MPEG4, H.264 or VC-1, can enable a substantial increase in either quality or capacity due to their increased efficiency, but use of such technologies would again require most viewers to purchase new reception equipment, since the vast majority of standard set-top boxes support only the older MPEG2 encoding. BSkyB were the first to suggest such a move to increase the number of channels available within their own share of space using MPEG4 on a subscription service. However, BSkyB's proposals were ultimately shelved following regulatory delays. The BBC, which ultimately broadcast high-definition television on Freeview in the DVB-T2 format adopted in 2009, initially considered an alternative method utilising spare capacity at night to allow the download of high definition programmes for later replay. In addition the BBC's Research and Development team invented a transmission method that doubles the effective bandwidth that could currently be delivered by each multiplex using "spatial multiplexing". While conventional analogue and digital terrestrial television signals are transmitted either vertically or horizontally polarised (providing protection against interference from other distant signals which may be transmitted on the same frequency, but will usually be planned to use the opposite polarisation), the proposed technique would have involved using the same frequency to transmit two different signals at once, one vertically