General election campaigning remains suspended in tribute to the Pope after Tony Blair delayed naming the date.
Tony Blair's plans have been put into 'mild disarray'
The prime minister had been expected to call the election on Monday, but the move was put on hold after he decided the timing was no longer appropriate.
He is now likely to ask the Queen on Tuesday to dissolve Parliament, ready for a 5 May election.
In Parliament, Mr Blair led tributes to former Labour premier James Callaghan, who died last month.
Mr Blair attended a special Vespers of the Dead service in memory of Pope John Paul II at London's Westminster Cathedral on Monday.
Conservative leader Michael Howard and Liberal Democrat leader Charles Kennedy were also among political guests at the service.
Monday: Vespers service in memory of the Pope and Parliament's tributes to James Callaghan
Tuesday: Prime minister expected to ask Queen to dissolve Parliament and announce a 5 May poll
Wednesday: Last prime minister's questions
Thursday: Possible last day when Parliament sits
Saturday: Royal wedding
Monday: Parliament formally dissolved
The delay in calling the election will not affect the timing of polling day which is still expected to be 5 May. To keep to that schedule, Parliament has to break up by 11 April.
If the election is called this week the government will rush to get its remaining legislation through Parliament.
MPs and peers are likely to stop sitting on Thursday, with Parliament formally dissolved the following Monday.
Ahead of a hectic parliamentary week, Home Secretary Charles Clarke has already admitted controversial plans for identity cards and a new offence of incitement to religious hatred could be dropped.
The Tory leader in the Lords, Lord Strathclyde, said he believed plans for ID cards were a "likely casualty" of the prime minister calling the election a year early.
He said whoever was elected would be able to "resurrect worthy bills" after 5 May.
He added: "The ID Card Bill is a very important piece of legislation, it raises some very serious questions, it raises questions about the relationship between the state and individuals.
"It is not coming into force for some years, so I think it could afford a delay of a few weeks."
It is not the first time Mr Blair has needed to change his election timetable. In 2001, he postponed the election because of the foot-and-mouth epidemic.