Draft Weights and Measures Act 1985 (Definitions of 'Metre' and 'Kilogram') (Amendment) Order 2020

Chi Onwurah Excerpts

Tuesday 2nd June 2020 General Committees

[Chi Onwurah (Newcastle upon Tyne Central) (Lab)]

It is a great pleasure to serve under your chairmanship, Mr Hollobone, and to take part in this debate. Our country has a proud scientific tradition, from Isaac Newton to Stephen Hawking, and from Ada Lovelace to Rosalind Franklin. Today we have Lesley Yellowlees, Jocelyn Bell Burnell and Newcastle-born Peter Higgs, who discovered the Higgs boson. Britain’s scientific giants have bestrode the world, and our science sector continues to lead the world, powering our economy in the process. Isaac Newton famously discovered gravity and, with Cavendish, identified the gravitational constant. He was one of the first fellows of the Royal Society and, like the Royal Society, I welcome these measures to redefine important constants —I say redefine, but in reality it is clarifying the definition in scientific terms.

Social distancing measures—and, at this very moment, parliamentary voting procedures—have ensured that the entire country is now expert in measuring 2-metre distances. I am pleased to note that this amendment will not send millions of us back out with our rulers to recalculate what we were once certain of. In fact, the amendment embeds scientific certainty and is a welcome example of following the science.

As shadow Science Minister, I am pleased to welcome this. Many may ask why or how these measurements are changing. The Minister said something on the subject. In the past, measurements were determined by physical standards, for example a foot or a finger’s width—body parts were a common method of measurements. As physical science developed, so did our measurements system.

As the Minister said, the latest definition of a kilogram goes by a piece of metal stored in a Parisian vault, Le Grand K. The problem is that if Le Grand K remains the fixed definition of a kilogram, damage to the cylinder in Paris would have knock-on effects on the value of a kilogram across the world. I do not want to be the one explaining that to wholesalers in my constituency when our markets are just re-opening.

Economics had the gold standard, and weights and measures had a physical standard. The new definition is based on a set of seven defining constants drawn from the fundamental constants of physics and other constants of nature. The kilogram is the last remaining measurement based on a physical standard. As the Minister outlined, scientific experts have spent decades researching and testing measurements. That research eventually led to the International Bureau of Weights and Measures adopting seven new base measurements in 2018. The new measurements were approved to come into effect a year ago. In the EU withdrawal agreement, the UK signed up to following EU member states in adopting the measures in 10 days’ time.

The statutory instrument is important because it will update the Weights and Measures Act 1985 with the new definitions for metre and kilogram, as approved by the IBWM, which consists of 102 countries. A kilogram will now be defined based on the most precise measurement ever, the Planck constant, which scientists have spent decades measuring to 10 parts per billion. The Planck constant can be expressed in terms of the SI units kilogram, metre and second.

Since metre and second are already defined by constants of nature, the value of a kilogram can be obtained without relying on comparisons with a metal block. A metre is defined by taking the fixed numerical value of the speed of light in a vacuum, c, to be 299,792,458 when expressed in the unit metres per second. It is very technical but accurate and rooted in scientific certainty.

The UK’s National Physical Laboratory, a world-leading metrology institute, played a key part in the redefinition of the kilogram. The changes ensure that units of measurement definitions are scientifically robust and globally accessible. I have spoken with the Royal Society, which in 2011 held an international meeting calling for change to the definition of the kilogram. It welcomes the news and applauds the contribution made by UK science.

If anyone is worried about what this draft order means for their lives, it is important to note that, as the Minister said, it will have no direct impact on businesses or consumers. The changes ensure uniformity across the world. Despite the changes, a kilogram will still have the same mass and a metre will still be the same length, so socially distanced outdoor exercise regimes can continue as successfully as they have been.

This is a useful technical instrument, but I have a couple of questions. The order’s explanatory memorandum states:

“It partly implements Commission Directive 2019/1258”.

If that is the case, what parts of the Commission directive are not being implemented, and why? Can the Minister reassure us that the UK will continue to reflect the European Union’s metrological definitions after the transition period? That is an important point for our scientists.

As the Minister outlined, part of the redefinition took place in the Weights and Measures Act 1985 (Amendment) and Units of Measurement Regulations 1986 (Amendment) Regulations 2019. Having looked at those regulations, I am not clear why we are doing it in two separate instruments, or whether there will be any issues in their interaction in practice.

Overall, the measure is a positive move that I and the stakeholders in the scientific community I have spoken to welcome. I hope that it reflects the Government’s commitment to embracing internationally recognised standards and aligning with our European neighbours, rather than moving away from them. Scientific evidence and certainty are key to the UK overcoming coronavirus and building a post-Brexit future, but so is collaboration.

I am glad that we are committed to abiding by European Union regulations as set out in the withdrawal agreement, as will be the case on 13 June when we adopt the new definitions of metre and kilogram, as that will necessarily support ongoing collaboration. It is a shame that this could not have been done a few weeks earlier, on World Metrology Day, but I will not hold the Minister responsible for that.

The draft order will make UK legislation consistent and up to date, reflecting the new scientific definitions that underpin the legal and scientific metrology framework around the world, and Opposition Members are happy to support it.