Following the King’s Speech, several bills may be introduced to Parliament just a day after the event and a mere fortnight after the General Election.

Ministers may also aim to schedule the Second Reading of some of these bills before the Summer recess. It is common practice for a new Government to move swiftly with its legislative programme following a General Election.

• In 2010 the Queen’s Speech took place on 25 May. The following day three bills – the Identity Documents Bill, the Local Government Bill and the Academies Bill – were laid before Parliament, two in the House of Commons and one in the House of Lords. The Academies Bill was the first to receive its Second Reading on 7 June 2010, a fortnight after it had been presented. By the Summer recess in late July a further seven bills had been presented, five in the Commons and two in the Lords.

• In 1997 the Queen’s Speech took place on 14 May. The following day two bills – the Referendums (Scotland and Wales) Bill and the National Health Service (Private Finance) Bill – were laid before Parliament, the former in the House of Commons and the latter in the House of Lords. Less than a week later a further five Bills were presented to Parliament. The Referendums Bill was the first to receive its Second Reading on 21 May 1997, just a week after it was presented to the House of Commons. By the 15 July, just two months after the Queen’s Speech, 19 bills had been introduced and 18 of these had received a Second Reading in the House in which they were presented.

Rachel Reeves has said that she will not hold a Budget without an independent forecast by the Office for Budget Responsibility if Labour win the General Election. The OBR requires 10 weeks’ notice to prepare an independent forecast for a Budget.

Assuming the earliest date she can give notice to the OBR to prepare a forecast is Friday 5 July, the earliest possible date that a Budget could be held is Friday 13 September.

Unless the Government decides that Parliament should sit during one or more of the three party conferences between 16 September and 4 October then it seems likely that the Budget will take place soon after Parliament returns from the conference recess the week commencing 7 October.

The earliest feasible date for the Budget would thus be 95 days after the General Election. This would be considerably later than Budgets that followed the last three changes of Government:

• in 1979 the Budget was held 39 days after the General Election;

• in 1997 the Budget was held 61 days after the General Election;

• in 2010 the Budget was held 46 days after the General Election.

The ‘Main Estimates’ setting out departmental spending plans for the current financial year are normally published in April for parliamentary approval in July. However, the Government did not publish this year’s ‘Main Estimates’ prior to calling the General Election.

House of Commons Standing Orders enable all departmental Estimates to be approved in a single ‘roll-up’ motion, but only if the motion is approved before 5 August each year. If approval is not secured before 5 August, then the abbreviated ‘roll-up’ procedure cannot be used, and each departmental Estimate would need to be approved separately which would be time-consuming.

The Government must publish and seek parliamentary approval of the Main Estimates before the Summer recess or departments will begin to run out of money by early Autumn.

The Estimates are scrutinised by departmental Select Committees. However, these are unlikely to be established before the Summer recess. The Estimates will therefore receive even less scrutiny than usual.

There is a 4-stage process to set up the majority of Select Committees:

• Stage 1: a determination by the Speaker of the number of Committee chairmanships due to each party, to reflect the composition of the House. The Speaker must inform the parties of this the day after his re-election.

• Stage 2: tabling of the motion allocating chairmanships to each party. This has to be done by the parties within two weeks of the King’s Speech. It is usually agreed by the House several days later. In recent Parliaments the motion has been approved on the 11th sitting day.

• Stage 3: election of chairs 14 calendar days after the House approves the motion allocating chairmanships to each party.

• Stage 4: nomination of Select Committee members by the parties following an internal ‘election’ process. This generally occurs about 30 sitting days after the first meeting of Parliament but Summer and party conference recesses means this can take up to three calendar months.

It is therefore probable that Select Committees will not be fully established until early October. Their early work could also be stymied if there are frontbench changes arising from opposition party leadership elections in the Autumn, which would then have a knock-on effect on Committee membership.

The Official Opposition is “the largest minority party which is prepared, in the event of the resignation of the Government, to assume office”, according to Erskine May.

The Leader of the Opposition is defined in the Ministerial and other Salaries Act 1975 as he or she who is “for the time being the Leader in that House of the party in opposition to Her [sic] Majesty’s Government having the greatest numerical strength in the House of Commons.”

If it is unclear which is the largest minority party or who the leader of that party is, the Act states that “the question shall be decided for the purposes of this Act by the Speaker of the House of Commons, and his decision, certified in writing under his hand, shall be final and conclusive.”

If two parties were to secure the same number of seats in the House of Commons it would therefore be for the Speaker of the House to decide which of them should be accorded the status of the Official Opposition. After the number of seats won, the criterion relied on by the Speaker in reaching a determination would most likely be each party’s share of the vote.

In a period of considerable political and electoral volatility it cannot be ruled out that the party accorded the status of the Official Opposition might change during the course of the Parliament owing to deaths in office, defections, mergers, resignations or suspensions. In the event of a material change in the number of seats held by the opposition parties mid-Parliament, it would be for the Speaker to decide whether the rights and responsibilities of the Official Opposition should be transferred to another party.

The identity of the second-largest minority party in the Commons might also change during the course of the Parliament. However, the definition in the House of Commons Standing Orders of the second-largest opposition party for the purpose of allocating Opposition Days explicitly states that it is the non-government party which “has the second largest number of members elected to the House as members of that party” (our italics for emphasis).

A party which had more seats than any other opposition party – apart from the Official Opposition - as a result of defections or a merger, would therefore not secure the rights of the second party of opposition because its new MPs would not have been elected to the House as members of that party.

There is precedent for such a scenario: when the Liberal Party and the Social Democratic Party merged in 1988 to form a new party, the Social and Liberal Democrats, they were the second largest opposition party in the House in terms of size, but the new party lost the entitlement to three Opposition Days previously held by the Liberal Party to the smaller Ulster Unionist Party.