A regular weekly rest period is a period of at least 45 consecutive hours. An actual working week starts at the end of a weekly rest period, and finishes when another weekly rest period is commenced, which may mean that weekly rest is taken in the middle of a fixed (Monday–Sunday) week. This is perfectly acceptable – the working week is not required to be aligned with the 'fixed' week defined in the rules, provided all the relevant limits are complied with. Alternatively, a driver can take a reduced weekly rest period of a minimum of 24 consecutive hours. If a reduction is taken, it must be compensated for by an equivalent period of rest taken in one block before the end of the third week following the week in question. The compensating rest must be attached to a period of rest of at least 9 hours – in effect either a weekly or a daily rest period.