Headline says it all, really. Just a reminder that there will be no Tube services to Blackfriars from today until late 2011, because of foundation work for a major redevelopment of the mainline station (and routine Tube engineering closures this weekend). The work will see the overground platforms stretch across the Thames, with a station entrance on the South Bank. The extension will allow 12 car trains as part of Network Rail's Thameslink upgrade programme. Other benefits include an enlarged ticket hall, step-free access and a curvy new building at the northern entrance.